Nanosecond pulser pulse generation

ABSTRACT

Some embodiments include a high voltage pulsing power supply. A high voltage pulsing power supply may include: a high voltage pulser having an output that provides pulses with an amplitude greater than about 1 kV, a pulse width greater than about 1 μs, and a pulse repetition frequency greater than about 20 kHz; a plasma chamber; and an electrode disposed within the plasma chamber that is electrically coupled with the output of the high voltage pulser to produce a pulsing an electric field within the chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,464 filed Jul. 27, 2018, titled “NANOSECOND PULSER SYSTEM,”which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,334 filed Jul. 27, 2018, titled “NANOSECOND PULSER THERMALMANAGEMENT,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,457 filed Jul. 27, 2018, titled “NANOSECOND PULSER PULSEGENERATION,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,347 filed Jul. 27, 2018, titled “NANOSECOND PULSER ADCSYSTEM,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,467 filed Jul. 27, 2018, titled “EDGE RING POWER SYSTEM,”which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,406 filed Jul. 27, 2018, titled “NANOSECOND PULSER BIASCOMPENSATION,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,468 filed Jul. 27, 2018, titled “NANOSECOND PULSER CONTROLMODULE,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/711,523 filed Aug. 10, 2018, titled “PLASMA SHEATH CONTROL FOR RFPLASMA REACTORS,” which is incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/789,523 filed Jan. 1, 2019, titled “EFFICIENT NANOSECOND PULSERWITH SOURCE AND SINK CAPABILITY FOR PLASMA CONTROL APPLICATIONS,” whichis incorporated by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/789,526 filed Jan. 1, 2019, titled “EFFICIENT ENERGY RECOVERY INA NANOSECOND PULSER CIRCUIT,” which is incorporated by reference in itsentirety.

This application claims priority to and is a continuation-in-part ofU.S. Non-Provisional patent application Ser. No. 16/523,840 filed Jul.26, 2019, titled “NANOSECOND PULSER BIAS COMPENSATION,” which isincorporated by reference in its entirety.

BACKGROUND

Producing high voltage pulses with fast rise times and/or fast falltimes is challenging. For instance, to achieve a fast rise time and/or afast fall time (e.g., less than about 50 ns) for a high voltage pulse(e.g., greater than about 5 kV), the slope of the pulse rise and/or fallmust be incredibly steep (e.g., greater than 10¹¹ V/s). Such steep risetimes and/or fall times are very difficult to produce especially incircuits driving a load with low capacitance. Such pulse may beespecially difficult to produce using standard electrical components ina compact manner; and/or with pulses having variable pulse widths,voltages, and repetition rates; and/or within applications havingcapacitive loads such as, for example, a plasma. Some plasma depositionsystems may not produce similar pulses and may not produce wafers asefficiently.

SUMMARY

Some embodiments include high voltage pulsing power supply that includesa high voltage pulser having an output that provides pulses with anamplitude greater than about 1 kV, a pulse width less than about 1 μs,and a pulse repetition frequency greater than about 20 kHz; a plasmachamber; and an electrode disposed within the plasma chamber that iselectrically coupled with the output of the high voltage pulser toproduce an electric field within the plasma chamber.

In some embodiments, an inductance between the output of the highvoltage pulser and at the electrode may be less than about 10 μH. Insome embodiments, the capacitance between the output of the high voltagepulser and ground may be less than about 10 nF.

In some embodiments, the high voltage pulsing power supply may alsoinclude a control module that measures the voltage of the output pulses.

In some embodiments, the high voltage pulsing power supply may alsoinclude a bias capacitor disposed between the high voltage pulser andthe electrode; and bias compensation power supply electrically coupledwith the high voltage pulser and the electrode, the bias compensationpower supply produces a voltage across the bias capacitor.

In some embodiments, the high voltage pulsing power supply may alsoinclude a resistive output stage electrically coupled with the highvoltage pulser and the electrode that removes charge from a load at fasttime scales.

In some embodiments, the resistive output stage includes an inductor anda capacitor arranged in series, wherein the inductor has an inductanceless than about 200 μH.

In some embodiments, the high voltage pulsing power supply may alsoinclude an energy recovery circuit electrically coupled with the highvoltage pulser and the electrode that removes charge from a load at fasttime scales.

In some embodiments, the high voltage pulsing power supply may alsoinclude a control module electrically coupled with the high voltagepulser that produces a low voltage signal that controls the pulse widthand the pulse repetition frequency of the output pulses.

In some embodiments, the high voltage pulsing power supply may alsoinclude a second high voltage pulser having an output that providespulses with an amplitude greater than about 1 kV, a pulse width lessthan about 1 μs, and a pulse repetition frequency greater than about 20kHz; and a second electrode disposed within the plasma chamber that iselectrically coupled with the output of the second high voltage pulserto produce a pulsing an electric field within the plasma chamber nearthe second electrode.

In some embodiments, the pulses from the high voltage pulser and thepulses from the second high voltage pulser differ in at least one ofvoltage, pulse width, and pulse repetition frequency.

In some embodiments, the high voltage pulsing power supply may alsoinclude a thermal management subsystem comprising one or more switchcold plates and one or more transformer core cold plates, wherein thehigh voltage pulser comprises a plurality of switches coupled with theone or more switch cold plates and a transformer coupled with the one ormore transformer core cold plates.

In some embodiments, the thermal management subsystem comprises a fluidthat flows through the switch cold plates and the core cold plates.

In some embodiments, the high voltage pulsing power supply may alsoinclude an enclosure having a volumetric dimension of less than 1 m³,wherein the high voltage pulser is disposed within the enclosure; and atleast three of the following a thermal management system, a controlsystem, a bias capacitor, a bias compensation power supply, a secondnanosecond pulser, a resistive output stage, and an energy recoverycircuit are disposed within the enclosure. In some embodiments, peakelectric field between any two components inside the enclosure is lessthan about 20 MV/m.

Some embodiments include a high voltage pulsing power supply thatincludes a high voltage pulser having an output that provides pulseswith an amplitude greater than about 1 kV, a pulse width less than about1 μs, and a pulse repetition frequency greater than about 20 kHz; aplasma chamber; and an electrode disposed within the plasma chamber thatis electrically coupled with the output of the high voltage pulser toproduce an electric field within the plasma chamber. In someembodiments, the high voltage pulsing power supply may also include acontrol module electrically coupled with the high voltage pulser, thecontrol module measures the voltage of the pulses at the electrode andthe control module modifies at least one of the voltage, pulse width,and pulse repetition frequency of the pulses in response to the measuredvoltage. In some embodiments, the high voltage pulsing power supply mayalso include a thermal management subsystem comprising a plurality ofcold plates coupled with the high voltage pulser.

In some embodiments, the high voltage pulser comprises a plurality ofswitches; and a transformer coupled with the plurality of switches andthe output, and having a transformer core. In some embodiments, theplurality of cold plates comprise: one or more switch cold platescoupled with the plurality of switches; and one or more transformer corecold plates coupled with the transformer core.

In some embodiments, the thermal management subsystem comprises a fluidthat flows through at least one of the plurality of cold plates.

In some embodiments, the control module measures one or more parametersof the thermal management subsystem and stops the high voltage pulserfrom outputting pulses in the event one of the one or more parameters isout of tolerance.

Some embodiments include a high voltage pulsing power supply comprisinga first high voltage pulser having a first output that provides pulseswith a first amplitude greater than about 1 kV, a first pulse width lessthan about 1 μs, and a first pulse repetition frequency greater thanabout 20 kHz; a second high voltage pulser having a second output thatprovides pulses with a second amplitude greater than about 1 kV, asecond pulse width less than about 1 μs, and a second pulse repetitionfrequency greater than about 20 kHz and a plasma chamber. In someembodiments, a first electrode may be disposed within the plasma chamberthat is electrically coupled with the first output of the first highvoltage pulser; and a second electrode may be disposed within the plasmachamber that is electrically coupled with the second output of thesecond high voltage pulser. In some embodiments, the high voltagepulsing power supply may also include a first bias capacitor disposedbetween the first high voltage pulser and the first electrode; and asecond bias capacitor disposed between the second high voltage pulserand the second electrode.

In some embodiments, the high voltage pulsing power supply may alsoinclude a first bias compensation power supply electrically coupled withthe first high voltage pulser and the first electrode, the first biascompensation power supply produces a voltage across the first biascapacitor; and a second bias compensation power supply electricallycoupled with the second high voltage pulser and the second electrode,the second bias compensation power supply produces a voltage across thesecond bias capacitor.

In some embodiments, the high voltage pulsing power supply may alsoinclude a thermal management subsystem comprising a plurality of coldplates coupled with the first high voltage pulser and the second highvoltage pulser.

In some embodiments, either or both the first bias capacitor or thesecond bias capacitor have a capacitance of more than about 1 nF.

Some embodiments of the invention include a nanosecond pulse generationsystem comprising: a first nanosecond pulser; a second nanosecondpulser; an interconnect board coupled with the first nanosecond pulserand the second nanosecond pulser; a resistive output stage coupled withthe interconnect board and ground, the resistive output stage comprisingat least a resistor and/or an inductor; and a chamber interface boardcoupled with the interconnect board via a capacitor.

In some embodiments, the nanosecond pulse generation system outputspulses with amplitudes of at least 8 kV.

In some embodiments, the nanosecond pulse generation system outputspulses with frequencies of 10 kHz or more.

In some embodiments, the nanosecond pulse generation system outputspulses with 30 kW or power.

In some embodiments, the resistive output stage includes a resistor witha resistance of 140 ohms.

In some embodiments, the resistive output stage includes a plurality ofresistor with a combined resistance of 140 ohms.

In some embodiments, the resistive output stage includes an inductorhaving an inductance of 15 μH.

In some embodiments, the resistive output stage includes a plurality ofinductors having a combined inductance of 15 μH.

These illustrative embodiments are mentioned not to limit or define thedisclosure, but to provide examples to aid understanding thereof.Additional embodiments are discussed in the Detailed Description, andfurther description is provided there. Advantages offered by one or moreof the various embodiments may be further understood by examining thisspecification or by practicing one or more embodiments presented.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the presentdisclosure are better understood when the following Detailed Descriptionis read with reference to the accompanying drawings.

FIG. 1 is a circuit diagram of a nanosecond pulser according to someembodiments.

FIG. 2 shows example waveforms produced by the nanosecond pulser.

FIG. 3 is another a circuit diagram of a nanosecond pulser according tosome embodiments.

FIG. 4 is a block diagram of a spatially variable wafer bias powersystem according to some embodiments.

FIG. 5 is a circuit diagram of a high voltage power system with a plasmaload according to some embodiments.

FIG. 6 is a circuit diagram of a high voltage power system with a plasmaload according to some embodiments.

FIG. 7 is a block diagram of a high voltage switch with isolated poweraccording to some embodiments.

FIG. 8 is a block diagram of an ADC control system for a nanosecondpulser system according to some embodiments.

FIG. 9 is a functional block diagram of a nanosecond pulser systemaccording to some embodiments.

FIG. 10 is a block diagram of the thermal management system according tosome embodiments.

FIG. 11 illustrates embodiments and/or arrangements of a switch coldplate system according to some embodiments.

FIG. 12 illustrate embodiments and/or arrangements of a cold plateaccording to some embodiments.

FIG. 13 illustrate embodiments and/or arrangements of a cold plateaccording to some embodiments.

FIG. 14 illustrate embodiments and/or arrangements of a cold plateaccording to some embodiments.

FIG. 15 shows an illustrative computational system for performingfunctionality to facilitate implementation of embodiments describedherein.

DETAILED DESCRIPTION

A nanosecond pulse generation system is disclosed. In some embodiments,the nanosecond pulse generation system may provide bursts of pulses withamplitudes of 2 kV or more into a plasma chamber. In some embodiments,the nanosecond pulse generation system may provide waveforms with pulserepetition frequencies greater than 10 kHz. In some embodiments, thenanosecond pulse generation system may include one or more nanosecondpulsers coupled with an NSP interconnect board and/or resistive outputstages.

In some embodiments, a high voltage nanosecond pulser system may pulsevoltages with amplitudes of more than about 2 kV to about 40 kV. In someembodiments, a high voltage nanosecond pulser system may switch withpulse repetition frequencies up to about 500 kHz or more. In someembodiments, a high voltage nanosecond pulser system may provide singlepulses of varying pulse widths from about 50 nanoseconds to about 1microsecond. In some embodiments, a high voltage nanosecond pulsersystem may switch at frequencies greater than about 10 kHz. In someembodiments, a high voltage nanosecond pulser system may operate withrise times less than about 20 ns up to about 200 ns.

In some embodiments, a high voltage nanosecond pulser system may includea number of components or subsystems. These may include one or more of aresistive output stage (e.g., resistive output stage 102), an energyrecovery circuit (e.g., energy recovery circuit 165), a spatiallyvariable wafer bias system (e.g., spatially variable wafer bias powersystem 400), a bias compensation circuit (e.g., bias compensationcircuit 104, 514 or 614), a control module (e.g., controller 825), afirst ADC (e.g., first ADC 820), a Multilam second ADC (e.g., second ADC845), a plurality of sensors, a thermal management system (e.g., thermalmanagement system 1000), etc.

FIG. 1 is a circuit diagram of a nanosecond pulser system 100 accordingto some embodiments. The nanosecond pulser system 100 can be implementedwithin a high voltage nanosecond pulser system. The nanosecond pulsersystem 100 can be generalized into five stages (these stages could bebroken down into other stages or generalized into fewer stages and/ormay or may not include the components shown in the figure). Thenanosecond pulser system 100 includes a pulser and transformer stage101, a resistive output stage 102, a lead stage 103, a DC biascompensation circuit 104, and a load stage 106.

In some embodiments, the nanosecond pulser system 100 can produce pulsesfrom the power supply with voltages greater than 2 kV, with rise timesless than about 20 ns, and frequencies greater than about 10 kHz.

In some embodiments, the pulser and transformer stage 101 can produce aplurality of high voltage pulses with a high frequency and fast risetimes and fall times. In all of the circuits shown, the high voltagepulser may comprise a nanosecond pulser.

In some embodiments, the pulser and transformer stage 101 can includeone or more solid state switches S1 (e.g., solid state switches such as,for example, IGBTs, a MOSFETs, a SiC MOSFETs, SiC junction transistors,FETs, SiC switches, GaN switches, photoconductive switches, etc.), oneor more snubber resistors R3, one or more snubber diodes D4, one or moresnubber capacitors C5, and/or one or more freewheeling diodes D2. One ormore switches and or circuits can be arranged in parallel or series.

In some embodiments, the load stage 106 may represent an effectivecircuit for a plasma deposition system, plasma etch system, or plasmasputtering system. The capacitance C2 may represent the capacitance ofthe dielectric material upon which a wafer may sit or capacitance C2 mayrepresent the capacitance between an electrode and a wafer which areseparated by a dielectric material. The capacitor C3 may represent thesheath capacitance of the plasma to the wafer. The capacitor C9 mayrepresent capacitance within the plasma between a chamber wall and thetop surface of the wafer. The current source 12 and the current sourceI1 may represent the ion current through the plasma sheaths.

In some embodiments, the resistive output stage 102 may include one ormore inductive elements represented by inductor L1 and/or inductor L5.The inductor L5, for example, may represent the stray inductance of theleads in the resistive output stage 102. Inductor L1 may be set tominimize the power that flows directly from the pulser and transformerstage 101 into resistor R1.

In some embodiments, the resistor R1 may dissipate charge from the loadstage 106, for example, on fast time scales (e.g., 1 ns, 10 ns, 50 ns,100 ns, 250 ns, 500 ns, 1,000 ns, etc. time scales). The resistance ofresistor R1 may be low to ensure the pulse across the load stage 106 hasa fast fall time t_(f).

In some embodiments, the resistor R1 may include a plurality ofresistors arranged in series and/or parallel. The capacitor C11 mayrepresent the stray capacitance of the resistor R1 including thecapacitance of the arrangement series and/or parallel resistors. Thecapacitance of stray capacitance C11, for example, may be less than 5nF, 2 nF, 1 nF, 500 pF, 250 pF, 100 pF, 50 pF, 10 pF, 1 pF, etc. Thecapacitance of stray capacitance C11, for example, may be less than theload capacitance such as, for example, less than the capacitance of C2,C3, and/or C9.

In some embodiments, a plurality of pulser and transformer stages 101can be arranged in parallel and coupled with the resistive output stage102 across the inductor L1 and/or the resistor R1. Each of the pluralityof pulser and transformer stages 101 may each also include diode D1and/or diode D6.

In some embodiments, the capacitor C8 may represent the straycapacitance of the blocking diode D1. In some embodiments, the capacitorC4 may represent the stray capacitance of the diode D6.

In some embodiments, the DC bias compensation circuit 104 may include aDC voltage source V1 that can be used to bias the output voltage eitherpositively or negatively. In some embodiments, the capacitor C12isolates/separates the DC bias voltage from the resistive output stageand other circuit elements. It allows for a potential shift from oneportion of the circuit to another. In some applications the potentialshift it establishes is used to hold a wafer in place. Resistance R2 mayprotect/isolate the DC bias supply from the high voltage pulsed outputfrom the pulser and transformer stage 101.

In this example, the DC bias compensation circuit 104 is a passive biascompensation circuit and can include a bias compensation diode D1 and abias compensation capacitor C15. The bias compensation diode C15 can bearranged in series with offset supply voltage V1. The bias compensationcapacitor C15 can be arranged across either or both the offset supplyvoltage V1 and the resistor R2. The bias compensation capacitor C15 canhave a capacitance less than 100 nH to 100 μF such as, for example,about 100 μF, 50 μF, 25 μF, 10 μF, 2μ, 500 nH, 200 nH, etc.

In some embodiments, the bias capacitor C12 may allow for a voltageoffset between the output of the pulser and transformer stage 101 (e.g.,at the position labeled 125) and the voltage on the electrode (e.g., atthe position labeled 124). In operation, the electrode may, for example,be at a DC voltage of −2 kV during a burst, while the output of thenanosecond pulser alternates between +6 kV during pulses and 0 kVbetween pulses.

The bias capacitor C12, for example, 100 nF, 10 nF, 1 nF, 100 μF, 10 μF,1 μF, etc. The resistor R2, for example, may have a high resistance suchas, for example, a resistance of about 1 kOhm, 10 kOhm, 100 kOhm, 1MOhm, 10 MOhm, 100 MOhm, etc.

In some embodiments, the bias compensation capacitor C15 and the biascompensation diode D1 may allow for the voltage offset between theoutput of the pulser and transformer stage 101 (e.g., at the positionlabeled 125) and the voltage on the electrode (e.g., at the positionlabeled 124) to be established at the beginning of each burst, reachingthe needed equilibrium state. For example, charge is transferred frombias capacitor C12 into bias compensation capacitor C15 at the beginningof each burst, over the course of a plurality of pulses (e.g., about5-100 pulses), establishing the correct voltages in the circuit.

In some embodiments, the DC bias compensation circuit 104 may includeone or more high voltage switches placed across the bias compensationdiode D1 and coupled with the power supply V1. In some embodiments, ahigh voltage switch may include a plurality of switches arranged inseries to collectively open and close high voltages.

A high voltage switch may be coupled in series with either or both aninductor and a resistor. The inductor may limit peak current throughhigh voltage switch. The inductor, for example, may have an inductanceless than about 100 μH such as, for example, about 250 μH, 100 μH, 50μH, 25 μH, 10 μH, 5 μH, 1 μH, etc. The resistor, for example, may shiftpower dissipation to the resistive output stage 102. The resistance ofresistor may have a resistance of less than about 1,000 ohms, 500 ohms,250 ohms, 100 ohms, 50 ohms, 10 ohms, etc.

In some embodiments, a high voltage switch may include a snubbercircuit.

In some embodiments, the high voltage switch may include a plurality ofswitches arranged in series to collectively open and close highvoltages. For example, the high voltage switch may, for example, includeany switch described in U.S. patent application Ser. No. 16/178,565,filed Nov. 1, 2018, titled “High Voltage Switch with Isolated Power,”which is incorporated into this disclosure in its entirety for allpurposes.

In some embodiments, a high voltage switch may be open while the pulserand transformer stage 101 is pulsing and closed when the pulser andtransformer stage 101 is not pulsing. When the high voltage switch isclosed, for example, current can short across the bias compensationdiode C15. Shorting this current may allow the bias between the waferand the chuck to be less than 2 kV, which may be within acceptabletolerances.

In some embodiments, the pulser and transformer stage 101 can producepulses having a high pulse voltage (e.g., voltages greater than 1 kV, 10kV, 20 kV, 50 kV, 100 kV, etc.), high pulse repetition frequencies(e.g., frequencies greater than 1 kHz, 10 kHz, 100 kHz, 200 kHz, 500kHz, 1 MHz, etc.), fast rise times (e.g., rise times less than about 1ns, 10 ns, 50 ns, 100 ns, 250 ns, 500 ns, 1,000 ns, etc.), fast falltimes (e.g., fall times less than about 1 ns, 10 ns, 50 ns, 100 ns, 250ns, 500 ns, 1,000 ns, etc.) and/or short pulse widths (e.g., pulsewidths less than about 1,000 ns, 500 ns, 250 ns, 100 ns, 20 ns, etc.).

FIG. 2 shows example waveforms produced by the nanosecond pulser system100. In these example waveforms, the pulse waveform 205 may representthe voltage provided by the pulser and transformer stage 101. As shown,the pulse waveform 205 produces a pulse with the following qualities:high voltage (e.g., greater than about 4 kV as shown in the waveform), afast rise time (e.g., less than about 200 ns as shown in the waveform),a fast fall time (e.g., less than about 200 ns as shown in thewaveform), and short pulse width (e.g., less than about 300 ns as shownin the waveform). The waveform 210 may represent the voltage at thesurface of a wafer represented in nanosecond pulser system 100 by thepoint between capacitor C2 and capacitor C3 or the voltage acrosscapacitor C3. The pulse waveform 215 represent the current flowing fromthe pulser and transformer stage 101 to the plasma. The nanosecondpulser system 100 may or may not include either or both diodes D1 or D2.

During the transient state (e.g., during an initial number of pulses notshown in the figure), the high voltage pulses from the pulser andtransformer stage 101 charge the capacitor C2. Because the capacitanceof capacitor C2 is large compared to the capacitance of capacitor C3and/or capacitor C1, and and/or because of the short pulse widths of thepulses, the capacitor C2 may take a number of pulses from the highvoltage pulser to fully charge. Once the capacitor C2 is charged thecircuit reaches a steady state, as shown by the waveforms in FIG. 2.

In steady state and when the switch S1 is open, the capacitor C2 ischarged and slowly dissipates through the resistive output stage 110, asshown by the slightly rising slope of waveform 210. Once the capacitorC2 is charged and while the switch S1 is open, the voltage at thesurface of the waver (the point between capacitor C2 and capacitor C3)is negative. This negative voltage may be the negative value of thevoltage of the pulses provided by the pulser and transformer stage 101.For the example waveform shown in FIG. 2, the voltage of each pulse isabout 4 kV; and the steady state voltage at the wafer is about −4 kV.This results in a negative potential across the plasma (e.g., acrosscapacitor C3) that accelerates positive ions from the plasma to thesurface of the wafer. While the switch S1 is open, the charge oncapacitor C2 slowly dissipates through the resistive output stage.

When the switch S1 is closed, the voltage across the capacitor C2 mayflip (the pulse from the pulser is high as shown in waveform 205) as thecapacitor C2 is charged. In addition, the voltage at the point betweencapacitor C2 and capacitor C3 (e.g., at the surface of the wafer)changes to about zero as the capacitor C2 charges, as shown in waveform210. Thus, the pulses from the high voltage pulser produce a plasmapotential (e.g., a potential in a plasma) that rise from a negative highvoltage to zero and returns to the negative high voltage at highfrequencies, with fast rise times, fast fall times, and/or short pulsewidths.

In some embodiments, the action of the resistive output stage, elementsrepresented by the resistive output stage 102, that may rapidlydischarge the stray capacitance C1, and may allow the voltage at thepoint between capacitor C2 and capacitor C3 to rapidly return to itssteady negative value of about −4 kV as shown by waveform 210. Theresistive output stage may allow the voltage at the point betweencapacitor C2 and capacitor C3 to exists for about % of the time, andthus maximizes the time which ions are accelerated into the wafer. Insome embodiments, the components contained within the resistive outputstage may be specifically selected to optimize the time during which theions are accelerated into the wafer, and to hold the voltage during thistime approximately constant. Thus, for example, a short pulse with fastrise time and a fast fall time may be useful, so there can be a longperiod of fairly uniform negative potential.

Various other waveforms may be produced by the nanosecond pulser system100.

FIG. 3 is a circuit diagram of a nanosecond pulser system 150 with thepulser and transformer stage 101 and an energy recovery circuit 165according to some embodiments. The energy recovery circuit, for example,may replace the resistive output stage 102 shown in FIG. 1. In thisexample, the energy recovery circuit 165 may be positioned on orelectrically coupled with the secondary side of the transformer T1. Theenergy recovery circuit 165, for example, may include a diode 180 (e.g.,a crowbar diode) across the secondary side of the transformer T1. Theenergy recovery circuit 165, for example, may include diode 160 andinductor 155 (arranged in series), which can allow current to flow fromthe secondary side of the transformer T1 to charge the power supply C7.The diode 160 and the inductor 155 may be electrically connected withthe secondary side of the transformer T1 and the power supply C7. Insome embodiments, the energy recovery circuit 165 may include diode 175and/or inductor 170 electrically coupled with the secondary of thetransformer T1. The inductor 170 may represent the stray inductanceand/or may include the stray inductance of the transformer T1.

When the nanosecond pulser is turned on, current may charge the loadstage 106 (e.g., charge the capacitor C3, capacitor C2, or capacitorC9). Some current, for example, may flow through inductor 155 when thevoltage on the secondary side of the transformer T1 rises above thecharge voltage on the power supply C7. When the nanosecond pulser isturned off, current may flow from the capacitors within the load stage106 through the inductor 155 to charge the power supply C7 until thevoltage across the inductor 155 is zero. The diode 180 may prevent thecapacitors within the load stage 106 from ringing with the inductance inthe load stage 106 or the bias compensation circuit 104.

The diode 160 may, for example, prevent charge from flowing from thepower supply C7 to the capacitors within the load stage 106.

The value of inductor 155 can be selected to control the current falltime. In some embodiments, the inductor 155 can have an inductance valuebetween 1 μH-500 μH.

In some embodiments, the energy recovery circuit 165 may include anenergy recovery switch that can be used to control the flow of currentthrough the inductor 155. The energy recovery switch, for example, maybe placed in series with the inductor 155. In some embodiments, theenergy recovery switch may be closed when the switch S1 is open and/orno longer pulsing to allow current to flow from the load stage 106 backto the high voltage load C7.

In some embodiments, the energy recovery switch may include a pluralityof switches arranged in series to collectively open and close highvoltages. For example, the energy recovery switch may, for example,include any switch described in U.S. patent application Ser. No.16/178,565, filed Nov. 1, 2018, titled “High Voltage Switch withIsolated Power,” which is incorporated into this disclosure in itsentirety for all purposes.

In some embodiments, the stray capacitance between the pulser andtransformer stage 101 and ground is less than about 10 nF.

In some embodiments, the nanosecond pulser system 150 may producesimilar waveforms as those shown in FIG. 2.

FIG. 4 is a block diagram of a spatially variable wafer bias powersystem 400 according to some embodiments. The spatially variable waferbias power system 400 may include the first high voltage pulser 425 andthe second high voltage pulser 430.

An interconnect board 405 may be electrically coupled with the firsthigh voltage pulser 425 and the second high voltage pulser 430 oradditional high voltage pulsers. In some embodiments, the interconnectboard 405 may provide a high DC voltage to each of the first highvoltage pulser 425 or the second high voltage pulser 430. In someembodiments, the interconnect board 405 may provide trigger signals tothe first high voltage pulser 425 or the second high voltage pulser 430.In some embodiments, the interconnect board 405 may provide low voltagepulses to the first high voltage pulser 425 or the second high voltagepulser 430.

In some embodiments, the interconnect board 405 may include a controlleror processor that includes one or more components of computationalsystem 1500. In some embodiments, one more sensors may be included thatmeasure a characteristic of the plasma chamber such as, for example, theelectric field on the surface of a wafer, the uniformity of an electricfield, the voltage on a first electrode, the voltage on a secondelectrode, the voltage across a resistor in one or more resistive outputstages or one or more energy recovery circuits. Based on the measurementfrom the sensors, the voltage, pulse width, or pulse repetitionfrequency of the first high voltage pulser 425 and the second highvoltage pulser 430 may be adjusted.

For example, if the voltage on the second electrode is measured anddetermined to be lower than the voltage on the first electrode, whichmay cause an electric filed nonuniformity (e.g., differences less thanabout 5%, 10%, 15%, or 20%) on the surface of the wafer. The controllermay adjust the pulse width of the control pulse being sent to the secondhigh voltage pulser 430, which may increase the voltage produced by thesecond high voltage pulser 430 (e.g., by increasing the capacitivecharging time) and, therefore, increasing the electric field on thesecond electrode. The process may repeat until the electric field acrossthe surface of the wafer is uniform (e.g., within 10%, 15%, 20%, 25%,etc.).

As another example, the voltages across a first resistive output stageand a second resistive output stages may be measured. These voltage cancorrespond to the current flowing from the chamber to ground as thecapacitance in the chamber discharges. This current may be proportionalto the ion energy. If the ion energy is at the first electrode and theion energy at the second electrode are nonuniform or misaligned (e.g., adifference greater than 10%, 20% or 30%), then the controller may adjustthe pulse width of the control pulse being sent to either the first highvoltage pulser 425 or the second high voltage pulser 430, which mayincrease the voltage produced by the nanosecond pulser (e.g., byincreasing the capacitive charging time) and, therefore, increasing theelectric field on the corresponding electrode.

In some embodiments, pulses from the first high voltage pulser 425 andthe second high voltage pulser 430 may pass to the energy recoverycircuit 440 and to the plasma chamber 435 via a chamber interface board.The energy recovery circuit 440, for example, may include the resistiveoutput stage 102 of nanosecond pulser system 100. As another example,the energy recovery circuit 440 may include the energy recovery circuit165. As another example, the energy recovery circuit 440 may not beused. As another example, an energy recovery circuit 440 may be coupledwith either or both the first high voltage pulser 425 or the second highvoltage pulser 430. In some embodiments, the plasma chamber 435 mayinclude a plasma chamber, an etch chamber, a deposition chamber, etc. Insome embodiments, the effective circuit of the plasma chamber 435 mayinclude load stage 106.

In some embodiments, the bias compensation circuit 410 may include anyor all components shown in bias compensation circuit 104, 514, or 614.In some embodiments, a plurality of bias compensation circuits may beused. For example, a first bias compensation circuit may be coupled withthe first high voltage pulser 425 and the first electrode; and a secondbias compensation circuit may be coupled with the second high voltagepulser 430 and the second electrode. The bias compensation circuit, forexample, may include a bias compensation capacitor C12, that may have acapacitance of 100 pF, 10 pF, 1 pF, 100 μF, 10 μF, 1 μF, etc.

While two high voltage pulsers are shown, any number may be used. Forexample, multiple rings of electrodes may be coupled with multiple highvoltage pulsers.

In some embodiments, the first high voltage pulser 425 may producepulses that are different than pulses produced by the second highvoltage pulser 430. For example, the first high voltage pulser 425 mayprovide pulses of at least 2 kV of pulsed output. In some embodiments,the second high voltage pulser 430 may provide pulses of at least 2 kVof pulsed output that are either the same or different than the pulsesprovided by the first high voltage pulser 425.

As another example, the first high voltage pulser 425 may produce pulseswith a first pulse repetition frequency and the second high voltagepulser 430 may produce pulses with a second pulse repetition frequency.The first pulse repetition frequency and the second pulse repetitionfrequency may be the same or different. The first pulse repetitionfrequency and the second pulse repetition frequency may be in phase orout of phase with respect to each other.

As another example, the first high voltage pulser 425 may produce afirst plurality of bursts with a first burst repetition frequency andthe second high voltage pulser 430 may produce a second plurality ofbursts with a second burst repetition frequency. Each burst may comprisea plurality of pulses. The first burst repetition frequency and thesecond burst repetition frequency may be the same or different. Thefirst burst repetition frequency and the second burst repetitionfrequency may be in phase or out of phase with respect to each other.

In some embodiments, the first high voltage pulser 425 and the secondhigh voltage pulser 430 may be water- or dielectric-cooled.

In some embodiments, the cable or transmission line between the outputof the first high voltage pulser 425 and the output of the second highvoltage pulser 430 and the plasma chamber 435 (or the electrodes) may begreater than 5 m, 10 m, 15 m, etc.

In some embodiments, the inductance between any of the followingcomponents may be less than about 100 pH: the first high voltage pulser425, the second high voltage pulser 430, and the plasma chamber 435.

In some embodiments, the stray capacitance between the first highvoltage pulser 425 or the second high voltage pulser 430 and ground isless than about 10 nF.

FIG. 5 is a circuit diagram of a high voltage power system with a plasmaload 500 according to some embodiments. The high voltage power systemwith a plasma load 500 is similar to high voltage power system with aplasma load 500.

In this embodiment, the bias compensation circuit 514, can include ahigh voltage switch 505 coupled across the bias compensation diode 506and coupled with power supply V1. In some embodiments, the high voltageswitch 505 may include a plurality of switches 505 arranged in series tocollectively open and close high voltages. For example, the high voltageswitch 505 may include the high voltage switch 700 described in FIG. 7.In some embodiments, the high voltage switch 505 may be coupled with aswitch trigger V4.

The high voltage switch 505 may be coupled in series with either or bothan inductor L9 and a resistor R11. The inductor L9 may limit peakcurrent through high voltage switch 505. The inductor L9, for example,may have an inductance less than about 100 μH such as, for example,about 250 μH, 100 μH, 50 μH, 25 μH, 10 μH, 5 μH, 1 μH, etc. The resistorR11, for example, may shift power dissipation to the resistive outputstage 102. The resistance of resistor R11, for example, may have aresistance of less than about 1,000 ohms, 500 ohms, 250 ohms, 100 ohms,50 ohms, 10 ohms, etc.

In some embodiments, the high voltage switch 505 may include a snubbercircuit. The snubber circuit may include resistor R9, snubber diode D8,snubber capacitor C15, and snubber resistor R10.

In some embodiments, the resistor R8 can represent the stray resistanceof the offset supply voltage V1. The resistor R8, for example, may havea high resistance such as, for example, a resistance of about 10 kOhm,100 kOhm, 1 MOhm, 10 MOhm, 100 MOhm, 1 GOhm, etc.

In some embodiments, the high voltage switch 505 may include a pluralityof switches arranged in series to collectively open and close highvoltages. For example, the high voltage switch 505 may include the highvoltage switch 700 described in FIG. 7. As another example, the highvoltage switch 505 may, for example, include any switch described inU.S. patent application Ser. No. 16/178,565, filed Nov. 1, 2018, titled“High Voltage Switch with Isolated Power,” which is incorporated intothis disclosure in its entirety for all purposes.

In some embodiments, the high voltage switch 505 may be open while thepulser and transformer stage 101 is pulsing and closed when the pulserand transformer stage 101 is not pulsing. When the high voltage switch505 is closed, for example, current can short across the biascompensation diode 506. Shorting this current may allow the bias betweenthe wafer and the chuck to be less than 2 kV, which may be withinacceptable tolerances.

In some embodiments, the high voltage switch 505 can allow the electrodevoltage (the position labeled 124) and the wafer voltage (the positionlabeled 122) to be quickly restored (e.g., less than about 100 ns, 200ns, 500 ns, 1 μs) to the chucking potential (the position labeled 121).

FIG. 6 is a circuit diagram of a high voltage power system with a plasmaload 600 according to some embodiments. The high voltage power systemwith a plasma load 600 includes a bias compensation circuit 614 thatincludes a second pulser 601 and switch 610.

The bias compensation circuit 614, can include a second pulser 601. Thesecond pulser 601, for example, may include one or more or all thecomponents of the pulser and transformer stage 101 shown in either FIG.1 or FIG. 3. For example, the pulser and transformer stage 101 mayinclude a nanosecond pulser or a high voltage switch as disclosed inthis document (e.g., FIG. 7 and related paragraphs). In someembodiments, the second pulser 601 may be configured to turn off whenthe pulser stage 101 is pulsing (e.g., during bursts), and the secondpulser 601 may be configured to turned on when the pulser stage 101 isnot pulsing (e.g., in between bursts)

The bias compensation circuit 614 may also include inductor L9 on thesecondary side of the transformer T2 and switch 610 may be coupled withvoltage source V6. The inductor L9 may represent the stray inductance ofthe bias compensation circuit 614 and may have a low inductance such as,for example, an inductance less than about 500 nH, 250 nH, 100 nH, 50nH, 25 nH, etc. In some embodiments, the voltage source V6 may representa trigger for the switch 610.

In some embodiments, the bias compensation circuit 614 may include ablocking diode D7. The blocking diode D7, for example, may ensurecurrent flows from the switch 610 to the load stage 106. The capacitorC14, for example, may represent the stray capacitance of the blockingdiode D7. The capacitance of capacitor C14, for example, may have a lowcapacitance such as, for example, less than about 1 nF, 500 pF, 200 pF,100 pF, 50 pF, 25 pF, etc.

In some embodiments, the switch 610 may be open while the pulser andtransformer stage 101 is pulsing and closed when the pulser andtransformer stage 101 is not pulsing to offset (or bias) the voltageprovided by the pulser stage.

In some embodiments, the switch 610 may include a plurality of switchesarranged in series to collectively open and close high voltages. In someembodiments, the switch 610 may include the high voltage switch 700described in FIG. 7. As another example, the high voltage switch 505may, for example, include any switch described in U.S. patentapplication Ser. No. 16/178,565, filed Nov. 1, 2018, titled “HighVoltage Switch with Isolated Power,” which is incorporated into thisdisclosure in its entirety for all purposes.

FIG. 7 is a block diagram of a high voltage switch 700 with isolatedpower according to some embodiments. The high voltage switch 700 mayinclude a plurality of switch modules 705 (collectively or individually705, and individually 705A, 705B, 705C, and 705D) that may switchvoltage from a high voltage source 760 with fast rise times and/or highfrequencies and/or with variable pulse widths. Each switch module 705may include a switch 710 such as, for example, a solid state switch.

In some embodiments, the switch 710 may be electrically coupled with agate driver circuit 730 that may include a power supply 740 and/or anisolated fiber trigger 745 (also referred to as a gate trigger or aswitch trigger). For example, the switch 710 may include a collector, anemitter, and a gate (or a drain, a source, and a gate) and the powersupply 740 may drive the gate of the switch 710 via the gate drivercircuit 730. The gate driver circuit 730 may, for example, be isolatedfrom the other components of the high voltage switch 700.

In some embodiments, the power supply 740 may be isolated, for example,using an isolation transformer. The isolation transformer may include alow capacitance transformer. The low capacitance of the isolationtransformer may, for example, allow the power supply 740 to charge onfast time scales without requiring significant current. The isolationtransformer may have a capacitance less than, for example, about 100 pF.As another example, the isolation transformer may have a capacitanceless than about 30-100 pF. In some embodiments, the isolationtransformer may provide voltage isolation up to 1 kV, 5 kV, 10 kV, 25kV, 50 kV, etc.

In some embodiments, the isolation transformer may have a low straycapacitance. For example, the isolation transformer may have a straycapacitance less than about 1,000 pF, 100 pF, 10 pF, etc. In someembodiments, low capacitance may minimize electrical coupling to lowvoltage components (e.g., the source of the input control power) and/ormay reduce EMI generation (e.g., electrical noise generation). In someembodiments, the transformer stray capacitance of the isolationtransformer may include the capacitance measured between the primarywinding and secondary winding.

In some embodiments, the isolation transformer may be a DC to DCconverter or an AC to DC transformer. In some embodiments, thetransformer, for example, may include a 110 V AC transformer.Regardless, the isolation transformer can provide isolated power fromother components in the high voltage switch 700. In some embodiments,the isolation may be galvanic, such that no conductor on the primaryside of the isolation transformer passes through or makes contact withany conductor on the secondary side of the isolation transformer.

In some embodiments, the transformer may include a primary winding thatmay be wound or wrapped tightly around the transformer core. In someembodiments, the primary winding may include a conductive sheet that iswrapped around the transformer core. In some embodiments, the primarywinding may include one or more windings.

In some embodiments, a secondary winding may be wound around the core asfar from the core as possible. For example, the bundle of windingscomprising the secondary winding may be wound through the center of theaperture in the transformer core. In some embodiments, the secondarywinding may include one or more windings. In some embodiments, thebundle of wires comprising the secondary winding may include a crosssection that is circular or square, for example, to minimize straycapacitance. In some embodiments, an insulator (e.g., oil or air) may bedisposed between the primary winding, the secondary winding, or thetransformer core.

In some embodiments, keeping the secondary winding far from thetransformer core may have some benefits. For example, it may reduce thestray capacitance between the primary side of the isolation transformerand secondary side of the isolation transformer. As another example, itmay allow for high voltage standoff between the primary side of theisolation transformer and the secondary side of the isolationtransformer, such that corona and/or breakdown is not formed duringoperation.

In some embodiments, spacings between the primary side (e.g., theprimary windings) of the isolation transformer and the secondary side ofthe isolation transformer (e.g., the secondary windings) can be about0.1″, 0.5″, 1″, 5″, or 10″. In some embodiments, typical spacingsbetween the core of the isolation transformer and the secondary side ofthe isolation transformer (e.g., the secondary windings) can be about0.1″, 0.5″, 1″, 5″, or 10″. In some embodiments, the gap between thewindings may be filled with the lowest dielectric material possible suchas, for example, vacuum, air, any insulating gas or liquid, or solidmaterials with a relative dielectric constant less than 3.

In some embodiments, the power supply 740 may include any type of powersupply that can provide high voltage standoff (isolation) or have lowcapacitance (e.g., less than about 1,000 pF, 100 pF, 10 pF, etc.). Insome embodiments, the control voltage power source may supply 720 V ACor 240 V AC at 60 Hz.

In some embodiments, each power supply 740 may be inductivelyelectrically coupled with a single control voltage power source. Forexample, the power supply 740A may be electrically coupled with thepower source via a first transformer; the power supply 740B may beelectrically coupled with the power source via a second transformer; thepower supply 740C may be electrically coupled with the power source viaa third transformer; and the power supply 740D may be electricallycoupled with the power source via a fourth transformer. Any type oftransformer, for example, may be used that can provide voltage isolationbetween the various power supplies.

In some embodiments, the first transformer, the second transformer, thethird transformer, and the fourth transformer may comprise differentsecondary winding around a core of a single transformer. For example,the first transformer may comprise a first secondary winding, the secondtransformer may comprise a second secondary winding, the thirdtransformer may comprise a third secondary winding, and the fourthtransformer may comprise a fourth secondary winding. Each of thesesecondary winding may be wound around the core of a single transformer.In some embodiments, the first secondary winding, the second secondarywinding, the third secondary winding, the fourth secondary winding, orthe primary winding may comprise a single winding or a plurality ofwindings wound around the transformer core.

In some embodiments, the power supply 740A, the power supply 740B, thepower supply 740C, and/or the power supply 740D may not share a returnreference ground or a local ground.

The isolated fiber trigger 745, for example, may also be isolated fromother components of the high voltage switch 700. The isolated fibertrigger 745 may include a fiber optic receiver that allows each switchmodule 705 to float relative to other switch modules 705 and/or theother components of the high voltage switch 700, and/or, for example,while allowing for active control of the gates of each switch module705.

In some embodiments, return reference grounds or local grounds or commongrounds for each switch module 705, for example, may be isolated fromone another, for example, using an isolation transformer.

Electrical isolation of each switch module 705 from common ground, forexample, can allow multiple switches to be arranged in a seriesconfiguration for cumulative high voltage switching. In someembodiments, some lag in switch module timing may be allowed ordesigned. For example, each switch module 705 may be configured or ratedto switch 1 kV, each switch module may be electrically isolated fromeach other, and/or the timing of closing each switch module 705 may notneed to be perfectly aligned for a period of time defined by thecapacitance of the snubber capacitor and/or the voltage rating of theswitch.

In some embodiments, electrical isolation may provide many advantages.One possible advantage, for example, may include minimizing switch toswitch jitter and/or allowing for arbitrary switch timing. For example,each switch 710 may have switch transition jitters less than about 500ns, 50 ns, 20 ns, 5 ns, etc.

In some embodiments, electrical isolation between two components (orcircuits) may imply extremely high resistance between two componentsand/or may imply a small capacitance between the two components.

Each switch 710 may include any type of solid state switching devicesuch as, for example, an IGBT, a MOSFET, a SiC MOSFET, SiC junctiontransistor, FETs, SiC switches, GaN switches, photoconductive switch,etc. The switch 710, for example, may be able to switch high voltages(e.g., voltages greater than about 1 kV), with high frequency (e.g.,greater than 1 kHz), at high speeds (e.g., a repetition rate greaterthan about 500 kHz) and/or with fast rise times (e.g., a rise time lessthan about 25 ns) and/or with long pulse lengths (e.g., greater thanabout 10 ms). In some embodiments, each switch may be individually ratedfor switching 1,200 V-1,700 V, yet in combination can switch greaterthan 4,800 V-6,800 V (for four switches). Switches with various othervoltage ratings may be used.

There may be some advantages to using a large number of lower voltageswitches rather than a few higher voltage switches. For example, lowervoltage switches typically have better performance: lower voltageswitches may switch faster, may have faster transition times, and/or mayswitch more efficiently than high voltage switches. However, the greaterthe number of switches the greater the timing issues that may berequired.

The high voltage switch 700 shown in FIG. 7 includes four switch modules705. While four are shown in this figure, any number of switch modules705 may be used such as, for example, two, eight, twelve, sixteen,twenty, twenty-four, etc. For example, if each switch in each switchmodule 705 is rated at 1200 V, and sixteen switches are used, then thehigh voltage switch can switch up to 19.2 kV. As another example, ifeach switch in each switch module 705 is rated at 1700 V, and sixteenswitches are used, then the high voltage switch can switch up to 27.2kV.

In some embodiments, the high voltage switch 700 may include a fastcapacitor 755. The fast capacitor 755, for example, may include one ormore capacitors arranged in series and/or in parallel. These capacitorsmay, for example, include one or more polypropylene capacitors. The fastcapacitor 755 may store energy from the high voltage source 760.

In some embodiments, the fast capacitor 755 may have low capacitance. Insome embodiments, the fast capacitor 755 may have a capacitance value ofabout 1 μF, about 5 μF, between about 1 μF and about 5 μF, between about100 nF and about 1,000 nF etc.

In some embodiments, the high voltage switch 700 may or may not includea crowbar diode 750. The crowbar diode 750 may include a plurality ofdiodes arranged in series or in parallel that may, for example, bebeneficial for driving inductive loads. In some embodiments, the crowbardiode 750 may include one or more Schottky diodes such as, for example,a silicon carbide Schottky diode. The crowbar diode 750 may, forexample, sense whether the voltage from the switches of the high voltageswitch is above a certain threshold. If it is, then the crowbar diode750 may short the power from switch modules to ground. The crowbardiode, for example, may allow an alternating current path to dissipateenergy stored in the inductive load after switching. This may, forexample, prevent large inductive voltage spikes. In some embodiments,the crowbar diode 750 may have low inductance such as, for example, 1nH, 10 nH, 100 nH, etc. In some embodiments, the crowbar diode 750 mayhave low capacitance such as, for example, 100 pF, 1 nF, 10 nF, 100 nF,etc.

In some embodiments, the crowbar diode 750 may not be used such as, forexample, when the load 765 is primarily resistive.

In some embodiments, each gate driver circuit 730 may produce less thanabout 1000 ns, 100 ns, 10.0 ns, 5.0 ns, 3.0 ns, 1.0 ns, etc. of jitter.In some embodiments, each switch 710 may have a minimum switch on time(e.g., less than about 10 μs, 1 μs, 500 ns, 100 ns, 50 ns, 10, 5 ns,etc.) and a maximum switch on time (e.g., greater than 25 s, 10 s, 5 s,1 s, 500 ms, etc.).

In some embodiments, during operation each of the high voltage switchesmay be switched on and/or off within 1 ns of each other.

In some embodiments, each switch module 705 may have the same orsubstantially the same (±5%) stray inductance. Stray inductance mayinclude any inductance within the switch module 705 that is notassociated with an inductor such as, for example, inductance in leads,diodes, resistors, switch 710, and/or circuit board traces, etc. Thestray inductance within each switch module 705 may include lowinductance such as, for example, an inductance less than about 300 nH,100 nH, 10 nH, 1 nH, etc. The stray inductance between each switchmodule 705 may include low inductance such as, for example, aninductance less than about 300 nH, 100 nH, 10 nH, 1 nH, etc.

In some embodiments, each switch module 705 may have the same orsubstantially the same (±5%) stray capacitance. Stray capacitance mayinclude any capacitance within the switch module 705 that is notassociated with a capacitor such as, for example, capacitance in leads,diodes, resistors, switch 710 and/or circuit board traces, etc. Thestray capacitance within each switch module 705 may include lowcapacitance such as, for example, less than about 1,000 pF, 100 pF, 10pF, etc. The stray capacitance between each switch module 705 mayinclude low capacitance such as, for example, less than about 1,000 pF,100 pF, 10 pF, etc.

Imperfections in voltage sharing can be addressed, for example, with apassive snubber circuit (e.g., the snubber diode 715, the snubbercapacitor 720, and/or the freewheeling diode 725). For example, smalldifferences in the timing between when each of the switches 710 turn onor turn off or differences in the inductance or capacitances may lead tovoltage spikes. These spikes can be mitigated by the various snubbercircuits (e.g., the snubber diode 715, the snubber capacitor 720, and/orthe freewheeling diode 725).

A snubber circuit, for example, may include a snubber diode 715, asnubber capacitor 720, a snubber resistor 716, and/or a freewheelingdiode 725. In some embodiments, the snubber circuit may be arrangedtogether in parallel with the switch 710. In some embodiments, thesnubber capacitor 720 may have low capacitance such as, for example, acapacitance less than about 100 pF.

In some embodiments, the high voltage switch 700 may be electricallycoupled with or include a load 765 (e.g., a resistive or capacitive orinductive load). The load 765, for example, may have a resistance from50 ohms to 500 ohms. Alternatively or additionally, the load 765 may bean inductive load or a capacitive load.

FIG. 8 is a block diagram of an ADC control system 800 for a nanosecondpulser system 100 (or nanosecond pulser system 300) according to someembodiments. In some embodiments, the ADC control system 800 may beelectrically coupled with the nanosecond pulser system 100 at one ormore locations. For example, a first HV signal 805A may include thevoltage signal at point 120 of the nanosecond pulser system 100, whichis between the pulser and transformer stage 101 and the biascompensation circuit 104. As another example, a second HV signal 805Bmay include the voltage signal at point 125 of the nanosecond pulsersystem 100, which is between the load stage 106 and the biascompensation circuit 104. In some embodiments, the first HV signal 805Aand the second HV signal 805B may include the voltage signals on eachside of the capacitor C12 of the bias compensation circuit 104. Anynumber of other signals may be received.

In some embodiments, the first HV signal 805A or the second HV signal805B may include the voltage signals provided to the load stage 106. Insome embodiments, the first HV signal 805A or the second HV signal 805Bmay include the voltage signals provided to the bias compensationcircuit 104. In some embodiments, the first HV signal 805A or the secondHV signal 805B may include the voltage signals provided to the leadstage 103. In some embodiments, the first HV signal 805A or the secondHV signal 805B may include the voltage signals provided to the pulserand transformer stage 101 may be measured. In some embodiments, thefirst HV signal 805A or the second HV signal 805B may include thevoltage signals provided to the resistive output stage 102.

The first HV signal 805A and the second HV signal 805B collectively orindividually may be referred to as the HV input signal 805.

In some embodiments, the HV input signal 805 may divided at voltagedivider 810. The voltage divider 810, for example, may include highvalue resistors or low value capacitors to divide the high voltage HVinput signal (e.g., greater than 1 KV) to a low voltage signal (e.g.,less than 50 V). The voltage divider 810, for example, may divide thevoltage with a 500:1 ratio. The voltage divider 810, for example, maydivide the HV input signal 805 voltage of 0-10 kV to a voltage of 0-20V. The voltage divider 810, for example, may divide the voltage withminimal power loss such as, for example, less than about 5 W of powerloss.

In some embodiments, the voltage divider 810 may include a low valuecapacitor, a large value capacitor, a low value resistor, and a largevalue resistor. The low value capacitor, for example, may comprise acapacitor that has a capacitance value of about 0.1, 0.5, 1.0, 2.5, 5.0,10.0 pf, etc. The large value capacitor, for example, may comprise acapacitor that has a capacitance value of about 500 pf. In someembodiments, the large value capacitor may have a capacitance value thatis about 50, 100, 250, 500, 1,000, 2,500, 5,000 pF, etc. greater thanthe capacitance value of the low value capacitor.

The low value resistor may have a resistance value of about 1.0, 2.5,5.0, 10, 25, 50, 100 kΩ, etc. The large value resistor may have aresistance value of about 0.5, 1.0, 2.5, 5.0, 10, 25, 50, 100 MΩ, etc.In some embodiments, the large value resistor may have a resistancevalue that is about 50, 100, 250, 500, 1,000, 2,500, 5,000 pF, etc.greater than the resistance value of the low value resistor. In someembodiments, the ratio of the low value capacitor to the large valuecapacitor may be substantially the same as the ratio of the low valueresistor to the large value resistor.

In some embodiments, the voltage divider 810 may receive the HV inputsignal and output a divided voltage signal. The divided voltage signal,for example, may be 100, 250, 500, 750, 1,000, etc. times smaller thanthe HV input signal.

In some embodiments, a filter 815 may be included such as, for example,to filter out any noise from the divided voltage signal.

In some embodiments, the divided voltage signal may be digitized by thefirst ADC 820. Any type of analog to digital converter may be used. Thefirst ADC 820 may produce a digitized waveform signal. In someembodiments, the first ADC 820 may capture data at 100, 250, 500, 1,000,2,000, 5,000 MSPS (megasamples per second or millions of samples persecond). In some embodiments, the digitized waveform signal may becommunicated to the controller 825 using any type of communicationprotocol such as, for example, SPI, UART, RS-232, USB, I2C, etc.

In some embodiments, the controller 825 may comprise any type ofcontroller such as, for example, an FPGA, ASIC, complex programmablelogic device, microcontroller, system on a chip (SoC), or anycombination thereof. In some embodiments, the controller 825 may includeany or all the components of the computational system 1500. In someembodiments, the controller 825 may include a standard microcontrollersuch as, for example, Broadcom Arm Cortex, Intel ARM Cortex, PIC32, etc.

In some embodiments, the controller 825 may receive a trigger signalfrom trigger 830. In other embodiments, the first ADC 820 may receivethe trigger signal from trigger 830. The trigger signal may provide thetiming of data acquisition at the first ADC 820. The trigger signal, forexample, may be a 5V TTL trigger. The trigger signal, for example, may,have a 50 ohm termination.

The digitized signal may then be output from the controller 825 via oneor more output ports such as, for example, a first output 835A or asecond output 835B (individually or collectively output 835). Theseoutputs may be coupled with a nanosecond pulser controller. Either orboth the output 835 may include an electrical connecter such as, forexample, an LVDS, TTL, LVTTL connector. Either or both the output 835may provide data to the nanosecond pulser controller using any type ofcommunication protocol such as, for example, SPI, UART, RS-232, USB,I2C, EtherCAT, Ethernet, Profibus, PROFINET.

In some embodiments, the ADC control system 800 may couple with thenanosecond pulser system 100 via a 8 mm Multilam receptacles on the ADCcontrol system 800.

In some embodiments, the second ADC 845 and the first ADC 820 maycomprise a single ADC device. In some embodiments, either or both thesecond ADC 845 or the first ADC 820 may be part of the controller 825.In some embodiments, the first ADC 820 may operate at a higheracquisition rate than the second ADC 845.

In some embodiments, the ADC control system 800 may include a second ADC845, which may receive inputs from a first sensor 850A and a secondsensor 850B (individually or collectively sensor 850) (or any number ofsensors). In some embodiments, the second ADC 845 may digitize analogsignals from the sensors 850. The sensors 850 may include, for example,a sensor that senses inlet water temperature, dielectric fluidtemperature, dielectric fluid pressure, chassis air temperature,voltage, fluid flow, fluid leak sensor, etc.

In some embodiments, the ADC control system 800 may monitor the voltage,frequency, pulse width, etc. of a given waveform and, in response, mayadjust the voltage, pulse repetition frequency, pulse width, burstrepetition frequency (where a burst includes a plurality of pulses),etc. provided to the input of the nanosecond pulser system 100. Forexample, the first ADC 820 may monitor the voltage amplitude of awaveform. This voltage data may be provided to the nanosecond pulsercontroller. The nanosecond pulser controller may adjust the amplitude orfrequency of the signal provided to the nanosecond pulser system 100.

In some embodiments, the ADC control system 800 may output arbitrarypulse signals via output 835 to one or more nanosecond pulser systems100. The output 835, for example, may include either fiber or electricconnections. In some embodiments, ADC control system 800 can include aplurality of output pulse channels (e.g., 1, 2, 5, 8, 20, 50, 100, etc.)that may, for example, be independent from each other. The plurality ofoutput pulse channels may, for example, output pulses withsub-nanosecond resolution.

For example, if the waveform voltage is less than a predeterminedvoltage, the first ADC 820 may send a signal to the nanosecond pulsersystem 100 to produce a waveform with a higher voltage. If the waveformvoltage is greater than a predetermined voltage, the first ADC 820 maysend a signal to the nanosecond pulser system 100 to produce a waveformwith a lower voltage.

As another example, if the pulse repetition frequency is greater than ananticipated pulse repetition frequency, the first ADC 820 may send asignal to the nanosecond pulser system 100 to produce a waveform with alower frequency. If the burst repetition frequency is less than ananticipated burst repetition frequency, the first ADC 820 may send asignal to the nanosecond pulser system 100 to produce a waveform with ahigher pulse repetition frequency.

As another example, if the waveform pulse width is longer than ananticipated pulse width, the first ADC 820 may send a signal to thenanosecond pulser system 100 to produce a waveform with a shorter orlonger pulse width. If the waveform duty cycle is shorter or longer thanan anticipated duty cycle, the first ADC 820 may send a signal to thenanosecond pulser system 100 to produce a pulses with the appropriateduty cycle.

The ADC control system 800 may monitor other waveform characteristicsand/or adjust these other characteristics.

In some embodiments, the ADC control system 800 may output arbitrarypulse signals via output 835 to one or more nanosecond pulser systems100. For example, the ADC control system may comprise an arbitrary pulsegenerator. The output 835, for example, may include either fiber orelectric connections. In some embodiments, ADC control system 800 caninclude a plurality of output pulse channels (e.g., 1, 2, 5, 8, 20, 50,100, etc.) that may, for example, be independent from each other. Theplurality of output pulse channels may, for example, output pulses withsub-nanosecond resolution. In some embodiments, the ADC control system800 may output pulses with resolution less than about 0.1 ns. In someembodiments, the ADC control system 800 may output pulses with jitterless than about 100 ps.

In some embodiments, each output pulse channel of the ADC control system800 may output pulses to a nanosecond pulser system 100 that triggersthe nanosecond pulser system 100. The ADC control system 800 may, forexample, adjust parameters of the output pulses in real-time or betweenpulses. These parameters may include pulse width, pulse repetitionfrequency, duty cycle, burst repetition frequency, voltage, number ofpulses in a burst, the number of burst, etc. In some embodiments, one ormore parameters may be adjusted or changed based on input to the ADCcontrol system 800 or based on a recipe or program.

For example, a recipe may include alternating high bursts and lowbursts. A high burst, for example, may include a plurality of pulseshaving long pulse width. A low burst, for example, may include aplurality of pulses having short pulse widths. The high burst and thelow burst may, for example, include the same number of burst ordifferent number of bursts. A short pulse width, for example, may be20%, 30%, 80%, 50%, etc. the width of the long pulse width. Thealternating high bursts and low bursts may include 5%, 20%, 50%, 100%,125%, 150%, etc. low bursts in relation to the number of high bursts.

In some embodiments, the control system 800 can adjust the pulse width,duty cycle, or pulse repetition frequency in conjunction with thedifferent steps of a plasma processing recipe, where each stage of therecipe may correspond to different ion current, chamber pressure, ordifferent gas in the chamber. Adjusting the pulse width, duty cycle, orpulse repetition frequency, may adjust the electric field and/or voltageat the wafer surface to optimize the performance of each step of therecipe.

In some embodiments, the ADC control system 800 comprises an electricalshield. An electrical shield, for example, can separate the high voltagecomponents from the low voltage components. An electrical shield, forexample, may be disposed physically between the voltage divider 810 andthe controller 825 or the first ADC 820. As another example, theelectric shield may be disposed physically between the nanosecond pulsersystem 100 and the controller 825 or the first ADC 820.

In some embodiments, the electric shield may be disposed physicallybetween resistors in the voltage divider 810. In some embodiments, theelectric shield may be disposed physically between capacitors in thevoltage divider 810.

In some embodiments, the electrical shield may comprise copper, nickel.In some embodiments, the electrical shield may comprise sheet metal,metal screen, or metal foam.

In some embodiments, the ADC control system 800 may monitor the sensors850 and take action. A number of examples are provided below.

In some embodiments, a nanosecond pulser system may include a coolingsubsystem. In some embodiments, the cooling subsystem may include afluid, such as, for example, either water or a dielectric fluid, thatflows through the cooling subsystem to remove heat from the nanosecondpulser system 100 (e.g., as shown in FIGS. 11-14). For example, one ofthe sensors 850 may include a flow rate sensor for fluid in the coolingsystem. If the controller 825 determines the flow rate is below a flowrate threshold, the ADC control system 800 will not allow the nanosecondpulser system 100 to turn on. If the controller 825 determines the flowrate is below a flow rate threshold, the ADC control system 800 willautomatically turn off the nanosecond pulser system 100. In someembodiments, the flow rate sensor (in some cases with the controller825) may be a flow rate interlock. A flow rate interlock, for example,may prevent the nanosecond pulser system 100 from turning on or may turnoff the nanosecond pulser system 100, if it is already on, if the flowrate is below the flow rate threshold.

For example, one of the sensors 850 may include a thermometer coupledwith the cooling subsystem. If the controller 825 determines thetemperature of the cooling subsystem (e.g., the temperature of thefluid) is above a water temperature threshold, the ADC control system800 will not allow the nanosecond pulser system 100 to turn on. If thecontroller 825 determines the temperature of the water is above thewater temperature threshold, the ADC control system 800 willautomatically turn off the nanosecond pulser system 100. A temperatureinterlock, for example, may prevent the nanosecond pulser system 100from turning on or may turn off the nanosecond pulser system 100, if itis already on, if the temperature is above the water temperaturethreshold.

For example, one of the sensors 850 may include a liquid level sensorfor a fluid reservoir in a cooling system. If the controller 825determines the reservoir liquid level is above a liquid level threshold,the ADC control system 800 will not turn on. If the controller 825determines the reservoir liquid level is above the liquid levelthreshold, the ADC control system 800 will automatically turn off thenanosecond pulser system 100. A liquid level interlock, for example, mayprevent the nanosecond pulser system 100 from turning on or may turn offthe nanosecond pulser system 100, if it is already on, if the liquidlevel is below the liquid level threshold.

In some embodiments, the nanosecond pulser system 100 may include anitrogen purge subsystem that pumps nitrogen into the nanosecond pulsersystem. The nitrogen purge system, for example, may introduce drynitrogen into an enclosure within which the high voltage nanosecondpulser system is disposed. For example, one of the sensors 850 mayinclude a nitrogen pressure sensor. If the controller 825 determines thenitrogen pressure level is below a pressure threshold the ADC controlsystem 800 will not turn on. If the controller 825 determines thenitrogen pressure level is below the pressure threshold the ADC controlsystem 800 will automatically turn off the nanosecond pulser system 100.A pressure interlock, for example, may prevent the nanosecond pulsersystem 100 from turning on or may turn off the nanosecond pulser system100, if it is already on, if the pressure is below the pressurethreshold.

In some embodiments, one of the sensors 850 may include a DC voltagesensor that may be coupled with a DC power supply in the nanosecondpulser system 100. For example, if multiple DC power supply systems areused in nanosecond pulser system 100 and during operation the voltagevaries by more than a set percentage (e.g., 1%, 5%, 10%, 20%, etc.) ormore than an absolute voltage (e.g., 5V, 10V, 50V, 100V, etc.) then theADC control system 800 may automatically turn off the nanosecond pulsersystem 100. As another example, if power supply systems are used andduring operation the voltage output differs by more than a percentagefrom a set voltage (e.g., 1%, 5%, 10%, 20%, etc.) or more than anabsolute voltage from the set voltage (e.g., 5V, 10V, 50V, 100V, etc.)then the ADC control system 800 may automatically turn off pulsing.

In some embodiments, output 835 may include an EtherCat module that maycommunicate with a third party system (e.g., an external system). Insome embodiments, the EtherCat module may comprise any type ofcommunication module. In some embodiments, the EtherCat may include oneor more components of the computational system 1500.

In some embodiments, the controller 825 may respond to the operation ofone or more interlocks. An interlock may, for example, include a 24Vinterlock, a dry N2 pressure interlock, a water flow interlock, adielectric flow interlock, a water reservoir level interlock, a watertemperature interlock, a dielectric temperature interlock, etc.

In some embodiments, the control system may control the operation of apulsing system such as, for example, pulse width, duty cycle, highvoltage set point, on/off, returns current output voltage, high voltagecurrent set point, returns current output current, enable high voltageoutput, returns high voltage enable state, emergency shutdown, etc.

In some embodiments, a user may interface with the control systemthrough an EtherCat module. A user, for example, may issue a PW commandto set the output pulse width. As another example, user may issue DUTYcommand to set the duty cycle. As another example, a user may issue aPWR command to turn the power on and begin operation of unit or off toend operation of the unit. As another example, the unit may continue tooperate as set until issued another command to change duty cycle, pulsewidth, or issued another PWR command to shut off.

In some embodiments, the ADC control system 800 may receive commandsfrom an external source in any type of communication protocols such as,for example, EtherCAT, LXI, Ethernet, Profibus, PROFINET, RS-232,ModBus, USB, UART, SPI, CC-Lin, etc.

FIG. 9 is a functional block diagram of a nanosecond pulser system 900according to some embodiments. In some embodiments, the nanosecondpulser system 900 may include all or some of the components shown orarranged in nanosecond pulser system 100 and/or nanosecond pulser system150.

In some embodiments, the nanosecond pulser system 900 may include achassis 905 within which some of the components are enclosed. In someembodiments, the nanosecond pulser system 900 may include an ADC controlmodule 912. The ADC control module 912 may include all or some of thecomponents shown in the ADC control system 800.

In some embodiments, the nanosecond pulser system 900 may include a biascompensation module 965 (e.g., all or some of the components of biascompensation circuit 104. bias compensation circuit 514 or biascompensation circuit 614) and/or a bias capacitor 910 (e.g., capacitorC12).

In some embodiments, the nanosecond pulser system 900 may include a heatexchanger subsystem 940.

In some embodiments, the nanosecond pulser system 900 may include a highvoltage DC power supply 950. The high voltage DC power supply may supplyDC power to bias compensation module 965 or nanosecond pulser 955.

In some embodiments, the nanosecond pulser system 900 may include aresistive output stage 920 (e.g., resistive output stage 102). In someembodiments, the nanosecond pulser system 900 may include any or allcomponents, arrangements, functionality, etc. shown and/or described inU.S. patent application Ser. No. 15/941,931, titled “High VoltageResistive Output Stage Circuit” filed on Mar. 30, 2018, which isincorporated in its entirety herein for all purposes.

In some embodiments, the nanosecond pulser system 900 may include anenergy recovery circuit 165 as shown in FIG. 3.

In some embodiments, the nanosecond pulser system 900 may include an HVMmodule 915. In some embodiments, the HVM module 915 may include anEtherCat slave module and/or a high voltage DC power supply module. TheHVM module 915 may include various connectors or ports for communicationwith external systems.

In some embodiments, the nanosecond pulser system 900 may include acontrol module 925. The control module 925 may include EtherCat slavemodule, a system on a chip module, and/or an FPGA.

In some embodiments, the nanosecond pulser system 900 may include asecond ADC module 930. The second ADC module 930 may include amicrocontroller (e.g., all or a portion of controller 825) and/or ananalog to digital converter (e.g., second ADC 845). The microcontroller,for example, may include any or all the components shown incomputational system 1500.

In some embodiments, the nanosecond pulser system 900 may have a modulardesign so that various modules may be easily replaced or repaired. Forexample, the nanosecond pulser system 900 may include a Power Entrymodule, an AC Heater Filters module, a Fast ADC module, a ControlModule, and/or an HVM. These modules, for example, may be slide inmodules. As another example, the nanosecond pulser system 900 mayinclude other modules such as, for example, the resistive output stageresistor and/or inductor modules, the thermal management system, and/ornanosecond pulsers. These modules may be accessed via removal or openingone or more covers on the body of the system.

In some embodiments, the nanosecond pulser system 900 may include apulse bias generation (PBG) module. This module may produce outputpulses at up to 8 kV and 900 kHz. This module, for example, may includetwo or more nanosecond pulsers and/or a resistive output stage.

In some embodiments, the nanosecond pulser system 900 may include anspatially variable wafer bias power system (e.g., any or all of thecomponents of the spatially variable wafer bias power system 400). Insome embodiments, this module may be a smaller version of the pulse biasgeneration subsystem, such as, for example, scaled to about 25% power.In some embodiments, this module may drive the edge of the waferseparately from the central portion of the wafer. Various otherimplementations may be used where different spatial regions of the wafermay be pulsed independently of each other.

In some embodiments, the nanosecond pulser system 900 may include an HVMmodule (e.g., a slide-in module). In some embodiments, this module mayprovide a DC chucking voltage.

In some embodiments, the nanosecond pulser system 900 may include an ACHeater Filter module (e.g., a slide-in module). In some embodiments,this module may filter the AC power going to the heater elements tominimize ground leakage current and avoid drawing excess power from thePBG through the heater elements to ground.

In some embodiments, the nanosecond pulser system 900 may includecontrol module and/or second ADC (e.g., a slide-in module). In someembodiments, this module may allow for the system to be controlled viaEtherCat. In some embodiments, this module may interface with externalDC supplies to control charge voltage and current. In some embodiments,this module may monitor internal sensors (e.g., temperature, flow,status, etc.) to ascertain system status.

In some embodiments, the nanosecond pulser system 900 may include powerdistribution (e.g., a slide-in module). In some embodiments, this modulemay provide an interface to plug in external power (e.g., HVDC and 3phase 208V). In some embodiments, this module may include an ACDC supplyto generate the needed control voltages for other modules inside the P1chassis. In some embodiments, this module may provide a powerdistribution network to get the needed voltages to the needed modules inthe system.

In some embodiments, the nanosecond pulser system 900 may include achassis. In some embodiments, the chassis may include a mechanicalassembly holding all the modules. In some embodiments, the chassis mayprovide an RF seal so that no EMI can enter or leak out of the system.In some embodiments, the chassis may be modular and/or include a removalfront cover to allow access to system internal components. In someembodiments, the chassis may allow “slide-in” modules from the side tobe easily replaced as needed.

In some embodiments, the nanosecond pulser system 900 may includethermal management subsystem 1000, which may include a heat exchanger, aplurality of fluid lines, and a plurality of cold plates. In someembodiments, the thermal management subsystem may provide cooling toother system components. In some embodiments, the thermal managementsubsystem may include cooling water (e.g., 5 gpm or more). In someembodiments, the thermal management subsystem may include a heatexchanger so that dielectric coolant can be circulated internally to thesystem, which may, for example, eliminate issues of arcing/capacitivecoupling that would occur if water was used throughout. In someembodiments, the thermal management subsystem may include cold platesfor the switches and cores on the NSPs, and for the ROS and snubberresistors.

In some embodiments, the nanosecond pulser system 900 may include asensors subsystem. In some embodiments, the sensor subsystem may provideall the needed sensors to monitor the status and operation of thesystem. In some embodiments, the sensor subsystem may includetemperature sensors that measure the temperature of key components(e.g., switches, cores, resistors, etc.) and/or of the dielectric fluidin the thermal management subsystem. In some embodiments, the sensorsubsystem may include flow/pressure sensors that may verify that thecoolant is circulating properly and/or is not leaking. In someembodiments, the sensor subsystem may include a sensor to verify theflow of nitrogen within the system, which may, for example, be necessaryto prevent condensation.

FIG. 10 is a block diagram of the thermal management system 1000according to some embodiments. In some embodiments, the thermalmanagement system 1000 may include a main manifold 1005 and a heatexchanger 1010. The heat exchanger 1010 may exchange heat between thecold side and the hot side of the thermal management system. The hotside may be fluidically coupled with any number of cold plates such thathot system fluid returned from the cold plates may be cooled by facilityfluid within the heat exchanger 1010. In some embodiments, system fluidmay include water, dielectric fluid, dielectric fluid Galden HT110,deionized water, glycol/water solutions, aromatic based dielectricfluids (e.g., DEB), silicate-ester based dielectric fluids (e.g., asCoolanol 25R), aliphatic based dielectric fluids (e.g., PAO), siliconebased dielectric fluids (e.g., Syltherm XLT), fluorocarbon baseddielectric fluids (e.g., FC-77), ethylene glycol, propylene glycol,methanol/water, potassium formate/acetate solutions, etc. In someembodiments, the facility fluid may include water such as, for example,tap water.

In some embodiments, the facility side of the heat exchanger 1010 mayreceive facility fluid (e.g., water) from an external fluid source 1015.In some embodiments, the external fluid source 1015 may include a fluidinlet and a fluid outlet. In some embodiments, the external fluid source1015 may include a facility fluid thermal management system. In someembodiments, the external fluid source may include one or more pumps toensure facility fluid is flowing through the external fluid sourceincluding the heat exchanger 1010.

In some embodiments, the heat exchanger 1010, for example, may exchangeheat from a hot side (e.g., various board components) to a cold side(e.g., a facility). In some embodiments, the cold side may include afacility fluid (e.g., water) and the hot side may include a system fluid(e.g., dielectric fluid). In some embodiments, the hot side may includeone or more switch cold plates 1041, 1051, one or more core cold plates1046, 1047, 1056, 1057, one or more resistor cold plates 1060, 1061,1062, 1063, snubber resistor cold plate 1070, 1071, one or more liquidto air heat exchangers 1080, 1081, a pump 1025, and/or a reservoir 1020,etc. The hot side may be a fully contained system. The cold side may becoupled with an external fluid supply and/or a thermal managementsystem. In some embodiments, the system fluid may be circulated fasterthan the facility fluid (e.g., twice as fast). In some embodiments, thesystem fluid may flow at a rate of about 1 to 100 gallons per minute orthe facility fluid may flow at a rate of about 1 to 100 gallons perminute. In some embodiments, the heat exchanger 1010 may facilitate heatexchange between the hot side and the cold side without transferringfluid between the hot side and the cold side.

In some embodiments, the hot side of the heat exchanger 1010 may becoupled with the cold plates, the reservoir 1020, the pump 1025, or themain manifold 1030 such as, for example, via one more pipes or tubes.

In some embodiments, the heat exchanger 1010 may include a scalableplate heat exchanger. In some embodiments, the heat exchanger 1010 mayinclude a shell and tube heat exchanger. In some embodiments, the heatexchanger 1010 may include a double pipe heat exchanger.

In some embodiments, the reservoir 1020 may allow for expansion orcontraction of the system fluid as the various components of the highvoltage nanosecond pulser system heat up under operation. In someembodiments, the reservoir 1020 may store excess system fluid to keepthe pump 1025 from potentially running dry. In some embodiments, thereservoir 1020 may be constructed in any number of ways such as, forexample, as a welded steel container or a polymer container. In someembodiments, the reservoir 1020 may have a customized shape that can besized or shaped to fit in any configuration or space. In someembodiments, the reservoir 1020 may have an opening on the top of thereservoir 1020 to allow the reservoir 1020 to be filled with additionalsystem fluid. In some embodiments, the reservoir 1020 may include apressure relief valve that can automatically open or close to allowpressure from within the reservoir to escape. In some embodiments, thereservoir 1020 may include multiple chambers or compartments that may beuseful to separate bubbles or reduce disturbances in the flow of thesystem fluid.

In some embodiments, the pump 1025 may pump system fluid through theheat exchanger 1010, the reservoir 1020, the main manifold 1030, tubes,pipes, or other components. The pump 1025, for example, may pump thesystem fluid with a flow rate of about 10-30 gallons per minute or about15-20 gallons per minute. In some embodiments, the pump may pump thesystem fluid with a flow rate of about 18 gallons per hour. In someembodiments, the pump 1025 may comprise a magnetic drive pump,centrifugal pump, regenerative turbine pump, mechanical seal pump, etc.In some embodiments, the pump 1025 may include a variable frequencydrive motor pump or a conventional single speed centrifugal pump. Insome embodiments, the pump may be wired so that the pump turns onautomatically when the entire system it powered on.

In some embodiments, the main manifold 1030 may distribute system fluidamong any number of cold plates. For example, the cold plates caninclude one or more switch cold plates 1041, 1051. Examples of switchcold plates are shown in FIG. 11. For example, the cold plates caninclude one or more core cold plates 1046, 1047, 1056, 1057. Examples ofcore cold plates are shown in FIGS. 12, 13, and 14.

In some embodiments, the core cold plates can interface with a toroidtransformer core to provide optimal cooling while minimizing the impacton transformer performance. In some embodiments, the core cold platesmay include inner or outer insulating rings so that a continuousconductive sheet primary winding of the transformer can be insulatedfrom the core cold plate. In some embodiments, a core cold plate can bemade of either a tube press fit into an aluminum ring or a largerdiameter copper tube can be flattened into a ring shape so that thereare less materials interacting. As another example, the core cold platecan be made from a solid piece of copper with a groove machined out ofthe inside to create an internal “tube” where then another piece ofmetal such as copper is then brazed on to the top.

For example, the cold plates can include one or more resistor coldplates 1060, 1061, 1062, 1063, one or more snubber resistor cold plates1070, 1071. Examples of the resistor cold plates and snubber resistorcold plates are shown in FIGS. 11 and 12. In some embodiments, theresistor cold plates may include machined or brazed copper so thatresistor cold plates can be as thin as possible while handling highpressures/velocities.

For example, the cold plates can include or one or more liquid to airheat exchangers 1080, 1081. The one or more liquid to air heatexchangers 1080, 1081 may cool air that circulates inside of thenanosecond pulser system. Fans disposed within the nanosecond pulsersystem may circulate this cool air through components that do not haveliquid-cooled cold plates attached to them. For example, the heatexchanger may be used to cool of diodes, gate drive circuits, switchingregulators, etc.

In some embodiments, the main manifold 1030 may include a plurality ofinterconnected orifices coupled with a plurality of connectors. Theplurality of connectors can be used to connect tubes with the variouscomponents. In some embodiments, each of the plurality of connectors mayinclude a quick connect connectors for ease of assembly, disassembly, ormaintenance. In some embodiments, each of the plurality of connectorsmay include barb connectors which may produce less drag on the systemfluid. In some embodiments, the manifold may have orifices of differentsizes to allow for different fluid flow rates to different components.

In some embodiments, the cold plates may include various cold platesthat can be configured or adapted to couple with various components. Insome embodiments, the cold plates may be designed using computationalfluid dynamics (CFD) to ensure proper cooling based on the specificoperating conditions (e.g., steady state flow rate, pressure,temperature, etc.) or geometry of each component.

In some embodiments, the switch cold plates and the core cold plates maybe designed and used to minimize size, stray capacitance, or strayinductance while removing as much heat as possible in a uniform way fromeach component.

In some embodiments, a core cold plate may introduce less than about 10pF, 1 pF, 100 nF, 10 nF, etc. of stray capacitance. For example, thestray capacitance measured between secondary winding and ground with thecore cold plate in place is less than about 10 nF (or about 10 pF, 1 pF,100 nF) greater than the stray capacitance between secondary winding andground without the core cold plate.

In some embodiments, a core cold plate may introduce less than about 1nH, 10 nH, 100 nH, 1 μH, 10 pH, etc. of stray inductance as measured onthe secondary side. For example, the stray inductance measured on thesecondary side of the transformer with the core cold plate may be lessthan 10 μH greater than the stray inductance on the secondary side ofthe transformer without the core cold plate. As another example, thestray inductance measured on the primary side of the transformer withthe core cold plate may be less than 10 nH greater than the strayinductance on the secondary side of the transformer without the corecold plate.

In some embodiments, a switch cold plate may introduce less than about10 nF of capacitance. For example, a switch may include a heat sink. Aswitch cold plate may be coupled with the heat sink. A first capacitancebetween the switch heat sink and ground may be determined without theswitch cold plate coupled with the heat sink. A second capacitancebetween the switch heat sink and ground may be determined with theswitch cold plate coupled with the heat sink. The difference between thefirst capacitance and the second capacitance may be less than about 10pF-10 nF of capacitance such as, for example, less than about 5 nF ofcapacitance. As another example, the stray capacitance between a switchcold plate and ground with the switch cold plate coupled with a switchheat sink is less than 5 nF greater than the stray capacitance betweenthe switch heat sink and ground with the first switch cold plateremoved.

In some embodiments, the switch cold plate may be coupled with theswitch heat sink such that the switch cold plate and the switch heatsink are at the same potential. This may also electrically couple theswitch cold plate to the collector (for an IGBT) or the drain (for aMOSFET) because the heat sink in switches can be connected to thecollector or drain.

In some embodiments, a thermal (or electrical) insulating material maybe disposed between a switch and switch cold plate.

In some embodiments, the switch cold plate and/or the core cold platemay have a geometry that is minimized.

In some embodiments, the various cold plates may be connected to themain manifold 1030 in series or in parallel.

In this example, two circuit boards 1040, 1050 are included that includea pulser and transformer stage (e.g., pulser and transformer stage 101)and a transformer core included on each board. Each board may includeone or more switch cold plates that may be in contact with one moreswitches (e.g., switch S1 in FIG. 1) and/or one or more core cold platesthat may be in contact with one transformer cores (e.g., transformer T2of FIG. 1). A plurality of resistor cold plates are coupled with theresistive output stage resistors (e.g., resistor R1 in FIG. 1), and thesnubber resistors (e.g., resistor R3 in FIG. 1). Each of these coldplates may be fluidically connected with the main manifold via copper orplex tubing. In some embodiments, the tubing may have a pipe size ofabout 0.1″, 0.2″, 0.5″, etc.

In some embodiments, thermal interface materials may be used to bridgethe gap between electrical components (e.g., switches, resistors,transformer cores, etc.) and a cold plate (e.g., one or more switch coldplates 1041, 1051, one or more core cold plates 1046, 1047, 1056, 1057,one or more resistor cold plates 1060, 1061, 1062, 1063, snubberresistor cold plate 1070, 1071, one or more liquid to air heatexchangers 1080, 1081). In some embodiments, thermal interface materialsmay be placed between tubing and a cold plate (e.g., one or more switchcold plates 1041, 1051, one or more core cold plates 1046, 1047, 1056,1057, one or more resistor cold plates 1060, 1061, 1062, 1063, snubberresistor cold plate 1070, 1071, one or more liquid to air heatexchangers 1080, 1081).

In some embodiments, thermal interface materials, for example, can bevery thin (e.g., as thin as 0.0005″ and up to a thickness of 0.1″), tominimize thermal resistance. In some embodiments, thermal interfacematerials can have more thickness or uneven thicknesses, to bridge gapsbetween objects with uneven surfaces or to provide structural rigidity.Thermal interface materials, for example, may be solid, such as, forexample, aluminum nitride, or may be deformable, such as, for example,conductive epoxy, thermal paste, or compressible thermal pads. Thermalinterface materials can be electrically insulating or electricallyconductive depending on application.

In some embodiments, a thermal epoxy can be used to mechanically andthermally attach the core cold plates to a transformer core. The thermalepoxy, for example, has a higher thermal conductivity than standard RTV.In some embodiments, thermally conductive tacky pads, which have ahigher thermal conductivity than thermal epoxy but are less structuralcan be used to couple each switch with a switch cold plate. In someembodiments, clips can be affixed to a switch cold plate with screws. Insome embodiments, a thin layer of thermal paste, which may be morethermally conductive than the tacky pads, can be used to couple aresistor and resistor core cold plates. In some embodiments, resistorscan be screwed down to the resistor cold plate surface, which mayprovide a constant uniform pressure to optimize heat transfer.

FIG. 11 illustrates embodiments and/or arrangements of a switch coldplate system 1100 (e.g., switch cold plate 1041, 1051). The switch coldplate system 1100 may include a plurality of switch cold plates 1105A,1105B, 1105C, 1105D, 1105E, 1105F, 1105G, 1105H (individually orcollectively switch cold plate 1105) arranged in a circular or octagonalarrangement (e.g., arranged axial around a central point) to couple witha corresponding circular or octagonal arrangement of switches (e.g.,arranged axial around a central point) (e.g., switch S1 in FIG. 1). Theswitch cold plates 1105 may be coupled together via tubing 1120, 1125.The tubing 1120, 1125 may, for example, conduct system fluid through thevarious switch cold plates 1105. In some embodiments, two parallel linesof tubing may connect the various switch cold plates 1105 and conductsystem fluid between the switch cold plates 1105.

In some embodiments, each switch cold plate 1105 may comprise a firstface and a second face. Each switch cold plate 1105 may include, forexample, one or two channels (or grooves) cut through the second facethat are sized and configured to securely couple with the tubing 1120,1125 such as, for example, having channel diameter that is substantiallysimilar to a tube diameter. In some embodiments, the first face may besubstantially flat and may couple with a surface of a switch (e.g., aflat portion of a switch) using a thermal interface material such as,for example, a thermally conductive paste or adhesive (e.g., aluminumnitride). The channels, for example, may be physically coupled with thetubing using a thermal conductive interface such as, for example, athermally conductive paste or adhesive (e.g., aluminum nitride). In someembodiments, the tubing 1120, 1125 may be press fit into the channel ofeach switch cold plate and/or then brazed to the inlet/outlet manifold1110 or the loop back manifold 1115 creating an octagon that may bescrewed to a circuit board where the switches are coupled.

In some embodiments, the second face of each switch cold plate 1105 maybe attached with 1, 2, 4, 8, etc. switches such as, for example, via athermally conductive paste or adhesive. In some embodiments, each switchcold plate 1105 may include one or more mounting holes that can becoupled with a switch.

In some embodiments, system fluid can enter the switch cold plate system1100 via an inlet/outlet manifold 1110 by entering the inlet/outletmanifold 1110 via an inlet port 1140 and exit the inlet/outlet manifold1110 via an outlet port 1145. In some embodiments, the inlet port 1140may include an inlet connector. In some embodiments, the outlet port mayinclude an outlet connector. In some embodiments, the inlet/outletmanifold 1110 may comprise an aluminum block of material. In someembodiments, the loop back manifold 1115 may comprise a metallic blockof material such as, for example, aluminum, brass, bronze, or copper. Insome embodiments, the loop back manifold 1115 may comprise a plastic.

In some embodiments, the inlet/outlet manifold 1110 may split the systemfluid into two separate paths: a first path may conduct the system fluidthrough tubing 1120 coupled four switch cold plates 1105G, 1105F, 1105E,1105D and back through tubing 1125 also coupled with these four switchcold plates 1105G, 1105F, 1105E, 1105D; and a second path may conductthe system fluid through tubing 1130 coupled with four switch coldplates 1105H, 1105A, 1105B, 1105C and back through tubing 1135 alsocoupled with these four switch cold plates 1105H, 1105A, 1105B, 1105C.

In some embodiments, the loop back manifold 1115 may receive the systemfluid from the tubing 1120 and return the system fluid back throughtubing 1125. In some embodiments, the loop back manifold 1115 mayreceive the system fluid from the tubing 1130 and return the systemfluid back through tubing 1135. This arrangement, for example, may helpto keep the temperature difference between the switches small and/or mayreduce the number of fittings.

In some embodiments, a thermal interface material may be placed betweentubing 1130 or tubing 1135 and each switch cold plate 1105.

In some embodiments, the inlet/outlet manifold 1110 may split the systemfluid into a first path the conducts the system fluid in one directionthrough the various switch cold plates 1105 in a one tubing (e.g.,tubing 1125) and a second path the conducts the system fluid in theopposite direction through the various switch cold plates 1105 inanother tubing (e.g., tubing 1120) without the loop back manifold 1115.

In some embodiments, a switch cold plates may maintain the surfacetemperature of the various switches to a temperature less than about 250C. In some embodiments, a switch cold plate may remove more than about 1W of heat from each switch.

FIG. 12, FIG. 13, and FIG. 14 illustrate embodiments and/or arrangementsof a cold plate 1200 (e.g., core cold plates 1046, 1047, 1056, 1057)according to some embodiments. In some embodiments, the core cold plate1200 can provide thermal dissipation to one or more transformer coressuch as, for example, a toroid shaped transformer core. In someembodiments, the core cold plate 1200 can be disposed between twotransformer cores 1210, 1211: one transformer core 1210 on one side ofthe core cold plate 1200 and the other transformer core 1211 on theother side of the core cold plate 1200. In some embodiments, embodimentsaddition core cold plate may be disposed on the other sides oftransformer cores 1210 and 1211.

In some embodiments, a system fluid may be pumped through the internaltube 1215 of the core cold plate 1200 at a rate of 0.1-10 gallons perminute.

In some embodiments, as shown in FIG. 13 and FIG. 14, the core coldplate 1200 may be made of a flat ring 1205 that may include internaltube 1215. In some embodiments, the flat ring 1205 may have a toroid ordonut shape and have an inner aperture. In some embodiments, the flatring may have an inner circumference or outer circumference. The flatring 1205 may comprise any metal such as, for example, aluminum, brass,steel, bronze, copper, etc. In some embodiments, the internal tube 1215may conduct the system fluid between the two transformer cores 1210,1211. The internal tube 1215, for example, may include copper tubing.

In some embodiments, the core cold plate 1200 includes the flat ring1205, the internal tube 1215, an inner ring 1230, or an outer ring 1235.In some embodiments, the inner ring 1230 or the outer ring 1235 maycomprise plastic or any other insulating material. In some embodiments,the inner ring 1230 may have an outer circumference that issubstantially similar to the inner circumference of the flat ring 1205.In some embodiments, the inner ring 1230 may be disposed within theinner aperture of the flat ring 1205. In some embodiments, the outerring 1235 may have an inner circumference that is substantially similarto the outer circumference of the flat ring 1205.

In some embodiments, the aperture of the flat ring 1205, inner ring1230, outer ring 1235, transformer core 1210, and transformer core 1211can be substantially aligned such as, for example, along an axis througha central axis of each of the aperture of the flat ring 1205, inner ring1230, outer ring 1235, transformer core 1210, and transformer core 1211.

In some embodiments, the inner ring 1230 or the outer ring 1235 may beattached to the inner and outer diameter of the transformer core toallow for standoff from any primary transformer windings and/orsecondary transformer windings that may be wound around the transformercore. In some embodiments, the inner ring 1230 or the outer ring 1235may reduce capacitive or inductive coupling between the core cold plate1200 and any primary transformer windings and/or secondary transformerwindings that may be wound around the transformer core.

In some embodiments, the internal tube 1215 may be coupled with inletconnector 1220 and outlet connector 1225. The inlet connector 1220 maybe coupled with inlet tubing 1240, for example, with clamp 1260 (ametallic or plastic clamp), a quick disconnect device, or soldered totogether. The inlet tubing 1240 may be coupled with connector 1250, forexample, via clamp 1260. The connector 1250, for example, may connectwith the main manifold 1030. The outlet connector 1225 may be coupledwith outlet tubing 1241, for example, with clamp 1260. The outlet tubing1241 may be coupled with connector 1251, for example, via clamp 1260.The connector 1251, for example, may connect with the main manifold1030.

In some embodiments, a core cold plate may maintain the surfacetemperature of a transformer core to a temperature less than about 200C. 25. In some embodiments, a core cold plate may remove more than about1 W of heat from a transformer core.

In some embodiments, the transformer core may include a ferrite core. Insome embodiments, the transformer core may comprise a toroid shape, asquare shape, a rectangular shape, etc. In some embodiments, thetransformer may comprise a cylindrical transformer.

In some embodiments, a thermal management system may include a number ofsensors (e.g., sensors 850) such as, for example, pressure sensorswithin one or more system fluid lines, a heat sensor (e.g., athermometer, thermistor, or thermocouple), liquid level sensor (e.g.,within a reservoir), or flow meters. In some embodiments, a flow metermay be disposed within or in line with one or more of the system fluidtubes. In some embodiments, a flow meter may be disposed within or inline with one or more of the water tubes. In some embodiments, a heatsensor may be disposed within a system fluid tube, at the inlet/outletmanifold or the outlet port of the switch cold plate system.

In some embodiments, these sensors may provide data to a controller oran interlock system that can adjust flow rates of either or both thesystem fluid or the facility fluid such as, for example, by changing apump speed or opening or closing various valves throughout the system.In some embodiments, a high voltage power supply may not turn on or mayautomatically turn off a certain sensor values (or averages) are or arenot achieved.

In some embodiments, the temperature of the system fluid may be measuredat the main manifold, before the heat exchanger, the pump output, aresistor cold plate, a core cold plate switch cold plate, a switch corecold plate, or any other location. In some embodiments, the airtemperature within the high voltage power supply may be monitored usingair temperature sensors such as, for example, surface mount sensors.

In some embodiments, the high voltage power supply may not turn onunless the flow rate of water is above a flow threshold such as, forexample, above about 1, 2.5, 5, 7.5, or 10 gallons per minute. In someembodiments, the high voltage power supply may not turn on unless theflow rate of water is below a flow threshold such as, for example, belowabout 10, 20, 50, or 100 gallons per minute. The water flow rate, forexample, may be measured at or near the water inlet port.

In some embodiments, the high voltage power supply may not turn onunless the flow rate of system fluid is above a flow threshold such as,for example, about 1, 2.5, 5, 7.5, or 10 gallons per minute. In someembodiments, the high voltage power supply may not turn on unless theflow rate of system fluid is below a flow threshold such as, forexample, below about 10, 20, 50, or 100 gallons per minute. The systemfluid flow rate, for example, may be measured at or near the pump.

In some embodiments, the high voltage power supply may not turn on ifthe input water temperature or the system fluid temperature is greaterthan a temperature threshold such as, for example, a temperaturethreshold of about 20 to 50 C, about 20 to 25 C, or about 20 C.

In some embodiments, the high voltage power supply may turn off if theinput water temperature or the system fluid temperature is greater thana temperature threshold such as, for example, a temperature threshold ofabout 50 to 70 C, about 50 to 60 C, or about 50 C.

In some embodiments, the high voltage power supply may turn off if thesystem fluid level in the reservoir (e.g., reservoir) is less than acertain amount or less than a percentage full such as, for example, lessthan about 30% to 75%, about 30% to 50%, or about 30% full.

In some embodiments, the high voltage power supply may turn off if thetemperature of system fluid exiting one or more switch cold plates isgreater than a temperature threshold such as, for example, 50 to 75 C,about 50 to 55 C, or about 50 C.

In some embodiments, the high voltage power supply may turn off or notturn on if the pressure in the system fluid system is below a pressurethreshold such as, for example, below about 0 to 1.5 bar, about 0.5 to 1bar, or about 1 bar. In some embodiments, the high voltage power supplymay turn off or not turn on if the pressure in the system fluid systemis above a pressure threshold such as, for example, above about 1.7 to 3bar, about 1.75 to 2 bar, about 1.75 bar. The pressure of the systemfluid, for example, may be measured within any dielectric tubes or pipescoupled with the main manifold.

In some embodiments, the high voltage power supply may turn off or notturn on if the if the pressure from a nitrogen sensor is below apressure threshold such as, for example, below the atmospheric pressure.

In some embodiments, the high voltage power supply may turn off or notturn on if the if a leak sensor indicates that a fluid leak (either thesystem fluid or the facility fluid) has occurred. The leak sensor, forexample, may include an optical sensor that indicates the presence ofliquid if the optical sensor is obscured.

In some embodiments, any of the sensors may comprise a switch sensor. Aswitch sensor, for example, may automatically close a switch in theevent a sensed threshold has been met. The switch, for example, may openor close a circuit.

In some embodiments, a plurality of fans may be disposed within the highvoltage nanosecond pulser system. For example, a plurality of fans maybe used to circulate air within the high voltage nanosecond pulsersystem. In this example, the various fans are placed so that they createan air flow pattern that circulates chilled air from the bottom upwardsaround the side of various modules, such as, for example, through acontrol interconnect board, and back down to various heat exchangersthat may be coupled to either or both the system fluid system or afacility fluid system.

An inert gas purge subsystem may be included according to someembodiments. In some embodiments, inert gas (e.g., nitrogen, helium,argon, etc.) may flow through the system to reduce the possibility ofcondensation developing on cooling components. In some embodiments,nitrogen may enter through an nitrogen bulkhead (e.g., on the bottomside of the chassis), pass through a filter, a nitrogen flow sensor, andout of an orifice limiter (e.g., limits the nitrogen flow to 10 litersper minute) into the high voltage nanosecond pulser system. In someembodiments, nitrogen may leave the chassis through another bulkhead,through gaps in the chassis or body, or at any another point in thechassis.

In some embodiments, a nanosecond pulser system can include an enclosureand one or more nanosecond pulsers with various subsystems can belocated within the enclosure. For example, two or more of the followingmay be located within the enclosure: thermal management system, acontrol system, a bias capacitor, a bias compensation power supply, asecond nanosecond pulser, a resistive output stage, or an energyrecovery circuit. In some embodiments, the enclosure may have a volumeless than about 1 m³.

In some embodiments, a plurality of resistive output stage resistors maybe coupled with each of the nanosecond pulsers. In some embodiments, aplurality of snubber resistors R3 may be coupled with each of thenanosecond pulsers. In some embodiments, various components may be slidemounted within the chassis.

In some embodiments, internal and slide-in modules may be connected withinterconnect PCBs. In some embodiments, PCBs may allow for signals to beshielded between ground layers to minimize EMI effects. In someembodiments, a rigid design is used that may be optimal forplacement/alignment of slide-in modules. In some embodiments, themodules may be screwed together and socket-style connections allow formodularity compared to cables or soldered connections.

In some embodiments, the peak electric field between any two componentsinside the enclosure may be less than about 20 MV/m.

Unless otherwise specified, the term “substantially” means within 5% or10% of the value referred to or within manufacturing tolerances. Unlessotherwise specified, the term “about” means within 5% or 10% of thevalue referred to or within manufacturing tolerances.

The computational system 1500, shown in FIG. 15 can be used to performany of the embodiments of the invention. As another example,computational system 1500 can be used perform any calculation,identification and/or determination described here. The computationalsystem 1500 includes hardware elements that can be electrically coupledvia a bus 1505 (or may otherwise be in communication, as appropriate).The hardware elements can include one or more processors 1510, includingwithout limitation one or more general-purpose processors and/or one ormore special-purpose processors (such as digital signal processingchips, graphics acceleration chips, and/or the like); one or more inputdevices 1515, which can include without limitation a mouse, a keyboardand/or the like; and one or more output devices 1520, which can includewithout limitation a display device, a printer and/or the like.

The computational system 1500 may further include (and/or be incommunication with) one or more storage devices 1525, which can include,without limitation, local and/or network accessible storage and/or caninclude, without limitation, a disk drive, a drive array, an opticalstorage device, a solid-state storage device, such as a random accessmemory (“RAM”) and/or a read-only memory (“ROM”), which can beprogrammable, flash-updateable and/or the like. The computational system1500 might also include a communications subsystem 1530, which caninclude without limitation a modem, a network card (wireless or wired),an infrared communication device, a wireless communication device and/orchipset (such as a Bluetooth device, an 802.6 device, a Wi-Fi device, aWiMax device, cellular communication facilities, etc.), and/or the like.The communications subsystem 1530 may permit data to be exchanged with anetwork (such as the network described below, to name one example),and/or any other devices described herein. In many embodiments, thecomputational system 1500 will further include a working memory 1535,which can include a RAM or ROM device, as described above.

The computational system 1500 also can include software elements, shownas being currently located within the working memory 1535, including anoperating system 1540 and/or other code, such as one or more applicationprograms 1545, which may include computer programs of the invention,and/or may be designed to implement methods of the invention and/orconfigure systems of the invention, as described herein. For example,one or more procedures described with respect to the method(s) discussedabove might be implemented as code and/or instructions executable by acomputer (and/or a processor within a computer). A set of theseinstructions and/or codes might be stored on a computer-readable storagemedium, such as the storage device(s) 1525 described above.

In some cases, the storage medium might be incorporated within thecomputational system 1500 or in communication with the computationalsystem 1500. In other embodiments, the storage medium might be separatefrom a computational system 1500 (e.g., a removable medium, such as acompact disc, etc.), and/or provided in an installation package, suchthat the storage medium can be used to program a general-purposecomputer with the instructions/code stored thereon. These instructionsmight take the form of executable code, which is executable by thecomputational system 1500 and/or might take the form of source and/orinstallable code, which, upon compilation and/or installation on thecomputational system 1500 (e.g., using any of a variety of generallyavailable compilers, installation programs, compression/decompressionutilities, etc.) then takes the form of executable code.

Numerous specific details are set forth herein to provide a thoroughunderstanding of the claimed subject matter. However, those skilled inthe art will understand that the claimed subject matter may be practicedwithout these specific details. In other instances, methods, apparatusesor systems that would be known by one of ordinary skill have not beendescribed in detail so as not to obscure claimed subject matter.

Some portions are presented in terms of algorithms or symbolicrepresentations of operations on data bits or binary digital signalsstored within a computing system memory, such as a computer memory.These algorithmic descriptions or representations are examples oftechniques used by those of ordinary skill in the data processing artsto convey the substance of their work to others skilled in the art. Analgorithm is a self-consistent sequence of operations or similarprocessing leading to a desired result. In this context, operations orprocessing involves physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals or the like. It should be understood, however, that all ofthese and similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining,” and “identifying” or the like refer toactions or processes of a computing device, such as one or morecomputers or a similar electronic computing device or devices, thatmanipulate or transform data represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of thecomputing platform.

The system or systems discussed herein are not limited to any particularhardware architecture or configuration. A computing device can includeany suitable arrangement of components that provides a resultconditioned on one or more inputs. Suitable computing devices includemultipurpose microprocessor-based computer systems accessing storedsoftware that programs or configures the computing system from ageneral-purpose computing apparatus to a specialized computing apparatusimplementing one or more embodiments of the present subject matter. Anysuitable programming, scripting, or other type of language orcombinations of languages may be used to implement the teachingscontained herein in software to be used in programming or configuring acomputing device.

Embodiments of the methods disclosed herein may be performed in theoperation of such computing devices. The order of the blocks presentedin the examples above can be varied—for example, blocks can bere-ordered, combined, and/or broken into sub-blocks. Certain blocks orprocesses can be performed in parallel.

The use of “adapted to” or “configured to” herein is meant as open andinclusive language that does not foreclose devices adapted to orconfigured to perform additional tasks or steps. Additionally, the useof “based on” is meant to be open and inclusive, in that a process,step, calculation, or other action “based on” one or more recitedconditions or values may, in practice, be based on additional conditionsor values beyond those recited. Headings, lists, and numbering includedherein are for ease of explanation only and are not meant to belimiting.

While the present subject matter has been described in detail withrespect to specific embodiments thereof, it will be appreciated thatthose skilled in the art, upon attaining an understanding of theforegoing, may readily produce alterations to, variations of, andequivalents to such embodiments. Accordingly, it should be understoodthat the present disclosure has been presented for purposes of examplerather than limitation, and does not preclude inclusion of suchmodifications, variations and/or additions to the present subject matteras would be readily apparent to one of ordinary skill in the art.

That which is claimed:
 1. A high voltage pulsing power supplycomprising: a high voltage pulser having an output that provides pulseswith an amplitude greater than about 1 kV, a pulse width less than about1 μs, and a pulse repetition frequency greater than about 20 kHz; aplasma chamber; and an electrode disposed within the plasma chamber thatis electrically coupled with the output of the high voltage pulser toproduce an electric field within the plasma chamber.
 2. The high voltagepulsing power supply according to claim 1, wherein an inductance betweenthe output of the high voltage pulser and at the electrode is less thanabout 10 μH.
 3. The high voltage pulsing power supply according to claim1, wherein the capacitance between the output of the high voltage pulserand ground is less than about 10 nF.
 4. The high voltage pulsing powersupply according to claim 1, further comprising a control module thatmeasures the voltage of the output pulses.
 5. The high voltage pulsingpower supply according to claim 1, further comprising: a bias capacitordisposed between the high voltage pulser and the electrode; and biascompensation power supply electrically coupled with the high voltagepulser and the electrode, the bias compensation power supply produces avoltage across the bias capacitor.
 6. The high voltage pulsing powersupply according to claim 1, further comprising a resistive output stageelectrically coupled with the high voltage pulser and the electrode thatremoves charge from a load at fast time scales.
 7. The high voltagepulsing power supply according to claim 6, wherein the resistive outputstage includes an inductor and a capacitor arranged in series, whereinthe inductor has an inductance less than about 200 μH.
 8. The highvoltage pulsing power supply according to claim 1, further comprising anenergy recovery circuit electrically coupled with the high voltagepulser and the electrode that removes charge from a load at fast timescales.
 9. The high voltage pulsing power supply according to claim 1,further comprising a control module electrically coupled with the highvoltage pulser that produces a low voltage signal that controls thepulse width and the pulse repetition frequency of the output pulses. 10.The high voltage pulsing power supply according to claim 1, furthercomprising: a second high voltage pulser having an output that providespulses with an amplitude greater than about 1 kV, a pulse width lessthan about 1 μs, and a pulse repetition frequency greater than about 20kHz; and a second electrode disposed within the plasma chamber that iselectrically coupled with the output of the second high voltage pulserto produce a pulsing an electric field within the plasma chamber nearthe second electrode.
 11. The high voltage pulsing power supplyaccording to claim 10, wherein the pulses from the high voltage pulserand the pulses from the second high voltage pulser differ in at leastone of voltage, pulse width, and pulse repetition frequency.
 12. Thehigh voltage pulsing power supply according to claim 1, furthercomprising a thermal management subsystem comprising one or more switchcold plates and one or more transformer core cold plates, wherein thehigh voltage pulser comprises a plurality of switches coupled with theone or more switch cold plates and a transformer coupled with the one ormore transformer core cold plates.
 13. The high voltage pulsing powersupply according to claim 12, wherein the thermal management subsystemcomprises a fluid that flows through the switch cold plates and the corecold plates.
 14. The high voltage pulsing power supply according toclaim 1, further comprising: an enclosure having a volumetric dimensionof less than 1 m³, wherein the high voltage pulser is disposed withinthe enclosure; and at least three of the following a thermal managementsystem, a control system, a bias capacitor, a bias compensation powersupply, a second nanosecond pulser, a resistive output stage, and anenergy recovery circuit are disposed within the enclosure.
 15. The highvoltage pulsing power supply according to claim 1, wherein the peakelectric field between any two components inside the enclosure is lessthan about 20 MV/m.
 16. A high voltage pulsing power supply comprising:a high voltage pulser having an output that provides pulses with anamplitude greater than about 1 kV, a pulse width less than about 1 μs,and a pulse repetition frequency greater than about 20 kHz; a plasmachamber; an electrode disposed within the plasma chamber that iselectrically coupled with the output of the high voltage pulser toproduce an electric field within the plasma chamber; a control moduleelectrically coupled with the high voltage pulser, the control modulemeasures the voltage of the pulses at the electrode and the controlmodule modifies at least one of the voltage, pulse width, and pulserepetition frequency of the pulses in response to the measured voltage;and a thermal management subsystem comprising a plurality of cold platescoupled with the high voltage pulser.
 17. The high voltage pulsing powersupply according to claim 16, wherein the high voltage pulser comprises:a plurality of switches; and a transformer coupled with the plurality ofswitches and the output, and having a transformer core; and wherein theplurality of cold plates comprise: one or more switch cold platescoupled with the plurality of switches; and one or more transformer corecold plates coupled with the transformer core.
 18. The high voltagepulsing power supply according to claim 16, wherein the thermalmanagement subsystem comprises a fluid that flows through at least oneof the plurality of cold plates.
 19. The high voltage pulsing powersupply according to claim 16, wherein the control module measures one ormore parameters of the thermal management subsystem and stops the highvoltage pulser from outputting pulses in the event one of the one ormore parameters is out of tolerance.
 20. A high voltage pulsing powersupply comprising: a first high voltage pulser having a first outputthat provides pulses with a first amplitude greater than about 1 kV, afirst pulse width less than about 1 μs, and a first pulse repetitionfrequency greater than about 20 kHz; a second high voltage pulser havinga second output that provides pulses with a second amplitude greaterthan about 1 kV, a second pulse width less than about 1 μs, and a secondpulse repetition frequency greater than about 20 kHz; a plasma chamber;a first electrode disposed within the plasma chamber that iselectrically coupled with the first output of the first high voltagepulser; a second electrode disposed within the plasma chamber that iselectrically coupled with the second output of the second high voltagepulser; a first bias capacitor disposed between the first high voltagepulser and the first electrode; and a second bias capacitor disposedbetween the second high voltage pulser and the second electrode.
 21. Thehigh voltage pulsing power supply according to claim 20, furthercomprising: a first bias compensation power supply electrically coupledwith the first high voltage pulser and the first electrode, the firstbias compensation power supply produces a voltage across the first biascapacitor; and a second bias compensation power supply electricallycoupled with the second high voltage pulser and the second electrode,the second bias compensation power supply produces a voltage across thesecond bias capacitor.
 22. The high voltage pulsing power supplyaccording to claim 20, further comprising a thermal management subsystemcomprising a plurality of cold plates coupled with the first highvoltage pulser and the second high voltage pulser.
 23. The high voltagepulsing power supply according to claim 20, wherein either or both thefirst bias capacitor or the second bias capacitor have a capacitance ofmore than about 1 nF.